SCP already has all the mappings that could make a decent cockpit - reflection/enviroment, diffuse, shine, glow mapping.
Bob recently showed us his awsome shadowing algorythm.
Bubpmapping is among the plans - so is overexposure.
So graphicaly SCP is up to the challenge.
It IS optional just like almost everything else with SCP.
The CODERS will have to tell hard it would be to implement.
It WON'T be too much of a resource drain.
Check out Mechwarrior 3 - the cockpits are pretty low-poly. What makes them exceptional is the awsomely done textures.
SCP already has a wast array of mappings to make the best out of it.
BTW a 3D cocpit offers a lot more than a 2D overlay, such as: padlock view, animated pilot model, acceleration effects
...and how about sniping a ship for yourself in drydock or in-launch? A very precise hit with a sniper weapon could blow the pilot leaving the ship undamaged - of course it wouldn't work if the shields are up, or if you didn't hit him through the acces hatch (roughly 30cm across).