Upgrading to FF, need to upgrade the glass too... 5D mkiii and 1 lens, or 6D and 2 lenses?

Question

I've been shooting for several years now, and my trusty 40D has been in dire need of an upgrade. I have had some good paying jobs in the last few months and I have some cash to play with. I've just been beating my head against the wall trying to figure out the best course of action.
I recognize that style determines one's needs, but my needs change. Sometimes it's portrait, studio/location... sometimes it's event, action... sometimes low light and long exposure. Increasingly, paid video is becoming part of my workflow.
I waited to see what the 70D would offer, I was impressed with the new AF system, fps, ISO performance, as well as the usefulness of the flip screen/wifi (more than I thought I would have been). The problem is that it's still a crop sensor, and still on the lower end of the "prosumer" line. I try not to let my ego get in the way too much, as I know that an expensive camera doesn't always make for a good photographer. However, after shooting the xxD line for many years (since the 10D), I would like to move up, and I don't know that I have the patience to wait for the 7D mkii.
I started looking at the 6D as the entry full frame option. The price is right, and if you put it together right, you can get the body and a good kit lens for around $2200. The limitations, as far as I can tell, would be AF system (number of points, and virtual lack of cross-type), fps, build quality, lack of headphone jack, single card slot, sync speeds, etc. If you are familiar with this camera, you are familiar with its functional shortcomings, especially when compared to the Nikon counterpart, the D600. However, I have to respect this camera in its sheer photo taking power, and that in some cases it carries better sensor ratings than the 5Dmkiii. The end result will be as good, if not better than the 5Dmkiii, so long as you are able to get the subject in focus and in frame due to the bogus AF system/fps rating. Seemingly, this camera will not do a lot of the work for you, not as much as it's big brother will, anyway.
I had the opportunity to shoot with a 5D mkiii, and I was blown away with every aspect of its layout and functionality. The AF system was stellar, the ISO performance was amazing, the IQ was well beyond anything I am used to. I was also able to use a full stable of L glass along with it, as well, so I could really express the potential of the camera. Every shot I got was in focus. The grouping options worked flawlessly, and I didn't have to focus/recompose as I have gotten so accustomed to. On the video side, I like the headphone jack and greater resistance to moire (supposedly). It felt solid in my hand, fit perfectly, and wasn't too heavy to carry around a 12 hour corporate gig (even with a broken finger). Was pretty stoked on it.
All of this being said, I need to upgrade the body. This much is clear. The limitation is that my lenses aren't up to par. Half of them are EF-S, and the EF lenses I have aren't much worth mentioning (28-135mm IS, 50mm f2.5 compact macro). The big question is, do I spend the money on the 5D for the greatly advanced features and functionality, and suck it up on the lenses for a while? Maybe just get the 24-105 and use that for basically everything? Or should I get the lesser 6D, and play with some classic lens options like the 16-35mm, 24-70mm, 70-200mm, etc? After all, the focus system wont matter if I don't have the lens to capture it anyway.
What is the better option?
1. Buy the more functional (expensive) body and maybe one lens to start.
2. Buy the less functional (cheaper) but equally IQ rated body and a few lenses, or other pro-business expenses?
Common knowledge seems to state that you invest in glass first.
In the past, I have felt limited by my camera's ability to keep up with low light and focus issues. I don't want to voluntarily step into an inferior system.  Conversely, I don't want to get saddled with a pricey body and no glass to use with it.  Are the technology gains in the 5D mkiii worth it if my budget is limited?
Just wondering if anyone has any insight to this dilemma?

Answer 1

Hi jadphoto, thanks for getting back.  I shot film for many years as well.  It gave me a really good foundation for making sure that you do everything as right as possible before hitting the shutter.  Making the change to digital was certainly revolutionary in the way that I was able to approach photography (cost, learning curve, instant gratification).  I was hoping that the move from crop to FF would be liberating and vision-changing, as well. 
Not needing a tripod as often would be awesome.  I do some long exposure stuff that will always require it, but I would like to be able to get some sharp, clean, hand-held images when I don't feel like lugging it around.  I was at a music festival recently, and basically all of my night shots were hand-held, or taken with the camera resting on something.  A lot of the shots were unusable because of blur or noise.  The lighting in those scenarios can be tough, and I've read that the 6D and 5D can basically focus in the dark.  Not needing external flash and a tripod would be great.  On the 40D, I don't like to push the ISO above 1250 (defintely the extreme end for that camera, in my opinion).
I was looking at the 24-70 2.8, or the 24-105 4 IS in that range.  The 24-70 has a lot of clout, and I like the lens.  I really like the bokeh/DOF of a 2.8.  However, the 24-105 has a little more reach, and the IS which is nice.  So I don't know that I would want to do double duty in that range, and like everything else, they seem to spread the awesome features around a bit.  I have really enjoyed the 28-135 over the years.  It has a solid build, really good optical results, but it can be a bit long on a crop sensor, so it gets limited indoor use.  I also recently dropped it from about chest high onto the street... while attached to the body... lens down (first time I've ever done something like that).  It slipped out of the tri-pod collar which was not fully secured.  The filter shattered, and I had to convince the barrel to go back into position so it would zoom properly, but everything alse still works fine.  Still sharp with fast AF.  Pretty incredible.  The 50 compact macro can be a lot of fun for still-life/detail/nature stuff, but I rarely take it out for portrait because the AF is loud and slow, and the results are not always spot-on.  Could be user error.  I might need to keep trying it out, but it doesn't get a lot of love in the paid portrait department.  My 50 1.8 had a cheap build too, but would take some pretty awesome photos (sometimes). 
I figured the rest of the kit would make sense once I settled on a mid-range.  I have an 11-18 EF-S that I would have to find a replacement for.  The 24mm on a FF was impressively wide, and might require less immediate attention.  Makes me realize the tunnel vision effect of the crop (good when you want it for reach)...  With that being said the 70, 105, and even 135 might need some help reaching on the FF.... and I've always wanted a fancy, beige/white 70-200.  I just don't know what would get the most use yet.  I was able to use a 70-200 2.8, and I loved the cross-room candids I could get when I wasn't all up on people.  A lot of time, they didn't know I was shooting them.  It's just a beast, though.  It's big, and not too discreet, which can serve the ego but can get you in trouble too.  I can imagine that it is a great tool to have when you need it.