We all know that GA loves his OMAPs, and I'm in no way saying that the Beagle board and OMAP3 systems aren't awesome, but I just can't see them being ready for this sort of application right now, both from a development point of view and from a cost point of view.
For the record as far as power consumption goes the x86 Geode equipment is quite conservative; the big difference between it and the OMAP/ARMs is the sleep/low power modes which in this scenario I don't see as a big factor.