I won't ask any questions like are there any emulators on PPC because I know there aren't.
When talking about NDS emulation on PPC people say: No way, until there is a PC emulator. And PocketPC has to be eon times stronger than the DS. But! I suppose we don't have to emulate the processor! Most of the popular PPCs use ARM (or xScale, which is, if I'm not mistaken, pretty similar - usually applications which run on ARM run on xScale) processors... So, it's just the question of RAM, like Pokemon Diamond rom is 128 Mb and I haven't seen any PPCs with 256 Mb RAM yet... 128 is also a rare case and usually is found in devices with RAM and ROM being one energy-requiring memory (just don't mix ROM and RAM).
So if there is any way to use ROM/Storage memory as part of RAM ( though that really would slow down access to it >.< ), I say it's possible to run something playable =)
What are your opinions on the matter?