Acorn? Aren't those a little high tech for the GP32? Unless you mean the BBC, in which case I guess not. There's no BBC emulators on GP32 to my knowledge but it is completely capable of emulating it. Lack of demand, I guess. Most of the popular BBC games were ported to other computers - Repton's to Spectrum, Exile to C64 and Dare Devil Denis had a 'sequel' on C64 which was pretty much identical to the original. As for the archimedes, I seriously doubt the GP32 can emulate that! And I don't know anything about more modern Acorn PC's, but I can't even begin to fathom what they'd be like...
I'm sure if you show someone a few BBC games they could knock up a decent emulator in a few days, though. It's all about wanting to make something!