MBP A1260 (Early 2008): Won't start, black screen, continuously lit LED - bad logic board?

Question

Hello everyone!
I'm having a rather serious issue with my MBP A1260 (early 2008) running the latest version of OSX 10.5. This is what happens (or doesn't happen) when I start it:
Usual start-up sounds (fans, HDD, Superdrive)
No chime at startup
Blank screen (I even can't see anything if I hold it against a light source)
The LED is on continuously. Bright at first, then after a second only dim
No backlight of the screen, no keyboard lighting
No reaction to pressing the volume or brightness keys, even after waiting for a while (the OS isn't password protected)
I tried a couple things and googled for a bit. This is what I've tried so far:
Plug in an external monitor - no signal
Removed the battery, used an old battery (which doesn't hold too much power anymore, but is working) - nothing
Restarted with alt-key pressed to bring up the bootcamp menu - nothing
Reset PRAM and NVRAM (P+R+opt+cmd at startup) - nothing
Reset SMC - nothing
Removed all RAM - nothing
Tried all combinations of RAM modules and RAM banks individually - nothing
As you can see, I've already tried quite a bit to get my computer back up, but there's been no success so far. As far as I can tell, this thing's logic board is broken, which would be a prohibitively expensive repair at about 600€ to 700€. I know the logic board is basically the whole computer, but that's an insane amount of cash for a four year old computer.
Do you wise people have any other ideas how to get this thing running again?
If not, I can only come up with three options:
Sell the MBP on ebay as broken
Buy another A1260 with a working logic board and exchange it or
Pay for the insanely expensive repair
Do you have other ideas?
Luckily, I have another early 2011 MBP, which I'm using right now. But to be honest, it may be the last mac I ever own.
Anyways, I'm thankful for all responses. I promise to keep you updated if I get the machine running again.

Answer 1

Any ideas?