Actually just because Genesi has posted the schematics for the Pegasos2 doesn't mean that the work needed to manufacture a new run of motherboards wouldn't still be quite daunting.
The actual layout of a complicated 4 layer motherboard and the calculations necessary to produce the correct trace lengths is incredibly complicated. We may have Genesi's schematics, but we don't have their actually circuit board layouts. THAT's where the real complications are.
While the Peg2 design could easily be upgraded to as high as 1.7GHz with a slightly more powerful processor (the 7448), we are still dealing with a relatively slow G4 level system.
Alternately, we could look at the 8610 or the 8641 (which Freescale has published a motherboard schematic for), but are we going to be able to get the components? I can't even get an 8641D out of Freescale because they claim they don't have any for sampling yet.
If we're all really serious about this, we need to consider what's out there (in terms of processors and components) and then set our goals toward something plausible.
I look forward to everyone's input on that idea.
Jim