As the X lead, I was fortunate enough to get one. Unfortunately, I ended up with the cheesy, half-broken one. I wasted a weekend on it last month, and in the past few days I've started looking at it again. It randomly locks up. Removing and reseating the processor card generally fixes this up, but not always. I've gotten it to the point where it's actually booting from a kernel on the hard disk and got a basic system running (and freezing, of course).
I'm trying to get a new one, but the upstream folks at Genesi, which makes the Pegasos, haven't been responding to my cries for help lately.
Jon pointed me at a couple of mailing list posts on the Pegasos, here and here.
So, that's where yesterday and tonight went.