Cheap trick to get more room sound (besides not close-miking): use two cardioids, one pointing at the singer and one pointing at 90 degrees out into the room - record on a separate track and you can control the amount of room ambience after the fact. Not as good of course as the real thing, but way better than nothing. On the plus side, you can even EQ the room sound separate from the main vocals if that floats yer boat.
-G