My thoughts;

Roland A-30 (84 keys I think, no sound)
Roland A-37 (76 keys, no sound)
Roland A-37 (76 keys no sound)

As I understand it, the Roland A- series are very good controllers, but no sound. You could get an Alesis NanoPiano, or Nanosynth though used on ebay for maybe 150 (give or take) just for your sounds in a band. Although those sounds won't blow anyone away, they sure should work in a mix. The A-xx serires controllers can control lots of functions, moreso than the next few 76 key synths that you could get used for 500 or less. (not sure of their controlling abilities:

Alesis QS7 (7.1 and 7.2)
Alesis Quadrasynth
Kurzweil SP76.

I have a Roland XP-80. Sometimes you can get one of those for under 800. I know they cost more than you mentioned, but it's a very good synth for 800 or under and a very decent controller.

Be blessed.
Bob
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