@Wittgenstein
The Pegasos is "newer" (not really in age) because they took
the TeronCX-design, and changed it nearly 100% to get the max. out
of the chips, while the A1 is just a slighly updated version of
the TeronCX.
The A1 is NOT a PoP-board as Hyperion plan to remove the OF-BIOS
(whicj was extremly buggy) and replace it with OpenBoot (sp),
which makes the whole board non-PoP.
The Pegasos is a PoP-baord with a self-developed OF-BIOS which
includes support for FFS-partitions (to boot from) and
"Disk_on_Chip" devices (probraly the 1st step to the eclipsis).
Oh and yes Pegsos+G4 is a reality, but only with the ZIF-carrier
and a G4-ZIF atm.