I think the point you miss about SCO's "evidence" is that they have been making massively expansive claims regarding what they own. Given what I've read of the history of Unix, these claims seem to be rather tenuous. Indeed, their lawsuit seems to be much more like a pump and dump than anything else. Look at SEC filings on the matter. I've also seen some analysis in the past month or so that would indicate that the thinly traded company is being manipulated greatly. The only reason I can see for SCO refusing to lay bare the code that allegedly infringes is because they have no leg to stand on when subjected to careful scrutiny.
Like many in the open source movement have said, if they show us what infringes, we will gladly remove it. The history of the linux kernel is quite well documented, and has mirrors far and wide. Once we know where to look for infringments, it will be quickly ripped out and replaced by even better code most likely. SCO is smoke and mirrors by a company that has collapsed to become nothing but a few lawyers trying to bludgeon us with the power of the state.