I think the matter is quite easy (much easier than the fuss Raffaele is making...:P ).
If Genesi knew that there were hundreds of people willing to pay some 850$+VAT for a 1.7 GHz, you'd see them around already. AFAIK the 1.7GHz modules for the PegasosII are ready since some time and have been tested. bPlan also has a 1.3 (or 1.4) GHz module around I think. But they know that Pegasos customers are a bit more savvy, and wouldn't part from such an amount of money for an upgrade. Personally I guess bPlan/Genesi could market such a module for much less (after all the G4@1GHz costs 199$ - or is it 249$.... much less than 500$ anyway).

The point it's that there wouldn't be much market unless the price was much lower on this side of the world (which is quite different from "the other side").

Kind regards,
Andrea