I played continuo for a Vivaldi Gloria at Christmas time this year. I took the top keyboard off my stack, made a temporary top that covered the back end of the keys. I placed it on a standard electronic keyboard stand. Took along my 2 active Behringer truth monitors, my little USB EMU 0404 and my 2 GB Dell laptop, a couple of MIDI cables, and a couple of Auido cables and I was set up and running in about 15 minutes. Used flutes from the free Enigma set, set up the Midi keyboard inputs (I forget how I did that, but could probably duplicate it) so that the one key board keyed both Swell and Great so I could have my choice of flutes to use. It worked incredibly well and I had people asking where the pipes were.
Since I used no 16's and no more than two stops at a time, there were no polyphony problems and the Behringer's handle the bottom end of 8's just fine.
John