Okay so i really like the S2000. I like iV-TECH even more. But i'm also a fan of big big torque. And i had the idea of replacing the F20 with a chevy LS1 (i measured; it fits), but then i'd be without V-TECH. So then i was thinking that if i could increase the stroke (and bore) of the engine then maybe it could make some decent torque. So my question is where could one go to do that and (getting techincal here) how much should one increase the stroke by? (stock F20 stroke is 3.57 inches)  

Don't even bother. Some company put out a 2.5L stroker kit a couple of years ago, and people were getting all kind of problems with it. It really didn't even make that much of a difference.
Just go with forced-induction. Same money, more power. And yes, you can get torque from a turbo.  

don't mess with the f20, its a perfect motor, just add some boost turbo or supercharger (i prefer turbo) and you will get a tone of torque, remember this saying, "boost is a replacement for displacement" not totally but a dang good one.  

A turbo setup would benefit the S2000 more than a Supercharger.

The F20 engine likes to rev.  High.  Very high.  At those high revs the superchargers belt would be sapping more power than should be legal, but a turbo would be LOVING it.