Ok well I'm not particularly knowledgeable about any of these consoles so just giving a heads up, but...
The GP2X, Wiz and Cannoo (all made by Gamepark Holdings) all seem to fit your bill. Sure there are other portable emulators out there, notably the "Dingoo" and just a plain ole PSP...
I'm new to this whole GP2X thing and got all caught up in the moment the other day, ended up purchasing one of these F300 VocaMasters with card/charger/new battery for 90$.
Now I hear the thing is essentially the least supported GP2X model ever-EVER! (ノಠ益ಠ)ノ ~ ┻━┻
So I'd really appreciate...