For the rare occasions that I fool around with a keyboard (really bought it for my sound engineering/producer course two years back) I have an EMU XBoard 25 (there were bigger versions too I believe). Main attraction for me were the 16 knobs, meaning less midi pages to go through if you want to get something done.
Only 25 but full-size keys. 16 saveable patches (settings). Both Midi Out (DIN) and Midi over USB. Oh and pitch and modulation wheels of course and finally a battery option, so you can run it off of (4 I think) AA batteries.
And I got it dirt cheap as it was the last showroom model. It was under 50 euro 🙂
Probably not what you are looking for, although if you need bigger the 69 key version might be worth a look up on ebay or in stores.
Greetinx,
C.