Yep if you just want something to emulate an Amiga either get an OUYA, FPGA Arcade or a good old MiniMiggy
I'm still in two minds about emulation of retro platforms, I guess it's pretty cool but it's still not the same as having the real HW. I've got a feeling that if I brought something like an OUYA for retro gaming that I end up spending most of my time playing newer games on it 
I historically buy Amigas, and play with them for a while, but later can't
justify having it around, and sell it.
Sooner, or later though, all of the genuine custom chips have got to fail,
and that's that, so we kind of do have to look at emulation at some stage.
A real A500 is tempting, but the extra hardware for LCD monitors,
and real floppy load times.. I'd prefer to cheat this time

Raspberry Pi also sounds like a good platform for a GPS program.