For less than $200, you can create a wireless send, and have people bring their portable radios and headphones. Of course, I always have the problem that more than half of the people don't own a little radio, much less one with headphones.
We bought a project box from Radio Shack and added 20 1/4" jacks in it, with a single input from a Sampson headphone amp.
We place the amp on a table, ask the choir to all bring in a set of headphones (even walkman style are sufficient).
3 overhead mics and we were good to go. It worked pretty good. It is admittedly a compromise, but recording a choir "live" always will be for a home rec'er.