Vaguely feasible thoughts:
-PCMCIA USB for the AGA models?
(I'm one of those who thinks USB hits the sweet spot for expanding anything you *can't*/*don't want to* slap a PPC on, and is 'important' in terms of giving the old machines a new lease on life... but the market is indeed pretty saturated right now. Anyone doing US importing of the Thylacine, I've lost track?)
-Everyone seems to like Coldfire. If you go through the trouble and expense... go through the trouble and expense of giving the same PCB some standalone capacity. Given physical limitations, I'm not sure if it'd be a good idea to try to wedge PCI onto such a beast, but something that can 'Flipper' into a backplane would be worth shooting for, or if not that, just something with the usual onboard CF/USB/Ethernet interfaces useful for the embedded Linux/BSD/maybe_even_AROS games.
-Not exactly hardware, and I've already pitched this to Fleecy and others, but an affordable hardware/software 'kit' to turn an old 'miggy into a networkable VNC client might be a good idea with the launch of 4 and the Pegasos line. Of course, this depends on having some VNC server action for the PowerPC "big boxes," but it'll keep people's classics out of landfill, and probably be reasonably popular.
There are probably some innovative (USB?) peripherals that could be used along with the above, depending how many cycles you can squeeze out of a 68000 or 020 already trying to handle IP and VNC... Along the lines of Griffin Tech's Mac lineup, but with more an eye to the 'networked home' business we were supposed to be shooting towards.
