Remove or reduce Mac OS after Windows install

Question

This may be an odd question, but first a little background.
I bought the 2011 MacBook Air as my first introduction into the world of Macs and thought it would also fulfil the occasional work duties due to the promises of how easy it is to integrate a Mac into a PC world since MS Office is available on both platforms.  For personal use Mac OS has been a breath of fresh air, intuitive gesture support makes browsing and editing photos fun again as well as playing around with using it as a media server, and Keynote has taken over for my presentation needs.
However working as an accountant means MS Excel, Outlook & Sage are central to my working day and due to various incompatibilities in the office, such as Mail & Outlook 2011 failing to work with our office's 2003 exchange server for one, and MS Excel 2011 being very much the poor cousin to Excel 2010 I ended up setting aside a 64Gb (of 256Gb) partition via Bootcamp to run Windows 7.
Little did I expect how good a Windows PC the MacBook Air makes!  Maybe it's the SSD drive but this thing easily lives up to the top of the range i7 HP desktops we use in the office so rather than using the Windows partition for the odd bit of remote working which was the plan two years ago, it is now my main work computer.  In fact after I added a couple of Displaylonk adapters I now have a four screen set up (3 x 22" 1080p Dell monitors plus laptop screen) which is the envy of the office.
So, I've since replaced my personal Mac needs with a quad core Mac Mini and haven't booted into Mac OS on the laptop for months and as you can probably guess but that 64Gb is running out quite fast.
I know I can't simply resize the partitions without causing possibly major future headaches and all this MBR/GPT/EFI stuff is unfortunately a little over my head so don't want to do anything crazy (like formatting the Mac OS partition which I've considered) without first getting some advice.
I don't really fancy wiping out the Bootcamp installation and starting again if at all possible, and don't mind keeping Mac OS around but I know that it is highly unlikely that I'll ever need it again on my Air and would probably jump for the MacBook Pro if I ever did need a portable Mac again.
Any help would be greatly appreciated :-).

Answer 1

Thanks guys, so I guess that means formatting the Mac partition from inside Windows definitely isn't a simple option then.
So... this leaves me with a couple more questions I'm afraid.
Firstly, I've read that Camptune can cause issues later down the road as it doesn't update the partition tables fully (or something?) which can lead to the possibility of losing Bootcamp later on - but that may only be when updating OSX, which is something I don't really plan on doing so may not be an issue for me?
and Secondly, how easy is it to completely purge OSX? 
I can't risk losing access to Windows for any length of time as my work life has become ridiculously hectic lately.  So I can't really risk trying this until I have had chance to set up another PC as back up just in case something goes wrong.  However with space rapidly becoming a premium on the Windows side it is a case of time is running out.