Well, MIDI is MIDI it doesn't care about congtrollers key range. You will be able to transpose using octave and key transpose. Since most patches and kits are designed for 61 note controllers (Pitch wise it is a usable range. How many times will you play a note on a synth at C-2??? If you really want to go that low then just set up your patch to do weird low overtones like that
) octave transpose isn't really going to be necessary most of the time.
Just to give you an idea I use a Motif ES8 (full 88 note keyboard) and most of my playing is done from C1 to C5 (rarely go higher or lower than that).
Really this stuff doesn't matter. If you are planning to use any sequencer software note and octave transpose isn't going to be an issue at all. Some people get away with using just two octave controllers. Really, this isn't something worth worrying about.
I would however get a controller with assignable knobs if you have that option. As long as the keyboard feels good to you and the knobs and controls are easy to deal with (some layouts get funny) go for it.
IF on the other hand you really like an A37 then you will most likely need an external fader controler thing (LOL) that I was mummbling on about before. I'm not really sure who makes those nowadays, but I'm sure you will find a few brands and types at the nearest music store. IF you only have one MIDI input on your MIDI interface though you will need an interface with more inputs. Ideally each MIDI device that you connect has to have it's own MIDI port. So if you plan on using a few hardware synths along with A37 and that controller fader thing (I think they are usually refered to as controllers but not keyboard controllers so I keep calling them funky names just to prevent confusion). you will require a MIDI interface with nmore than one IN/OUT. Well, you probably know that anyway.
Hey, just as a thought you might want to post your question at The Bar section here. I'm just curious about other opinions on your situation.
GOod luck anyway. From my point of view you should go with something that feels great, costs little and has assignable knobs. If there's an alternative to your original choice and it has knobs it would be worth considering.
-ED-