Hi

Just want to give my comments on this issue.

Long exposure is 1 way. If the room is small you can also play with the aperture and it should not effect the quality. It works for me.

Also if it is a dark room, are you sure that you want the pano to be way to bright . It will give you an unnatural presentation of the room, and ot will not be what the guest will experience. I recently made a panorama of a long hall in a castle where the light was poor as well. I kept the low light and the result came out very well. The atmosphere was capturen much better.

If you want the bright room you can always shoot in RAW and play around with photo shop. 

Hi Mate, I have encountered this lots, obviously use the lowest iso setting for less noise in the shot take a medium exposure so you have a nice histogram with no blowouts then stitch openthe raw pano in cs2 then go to image>adjust>shadow/highlights option and tweak it up

Good luck
Craig