for low light the Fuji Finepix F10 or F30
for very small size with amazing zoom range ( starting from 28mm which I personally like a lot )
Panasonic FX01 ( zoom 28mm - 102mm )
Ricoh Caplio R4 ( zoom 28mm - 200 mm )
for closeups of the musicians from distance:
Panasonic TZ1 ( zoom 35mm - 350mm )
the Panasonics and the Ricoh also have good functioning 'image stabilizers', very useful if using strong zoom or low light!
certainly the sound recordings will be disappointing, specially for tapers. I am not even sure if the cams mentioned all do record sound, but I think so. They all ( minus the Fuji F10 ) are very latest models.
please check:
http://www.dpreview.com/http://www.megapixel.net/html/reviews.php