Boston has a great Dark Cabaret scene... I recommend Beat Circus and Reverend Glasseye... both of whom I'm seeing this week

Couple of free Beat Circus mp3s from their new album here:
Beat Circus - Boy From Black Mountain
And lots of free Glasseye mp3s here (click Media > mp3s):
REVEREND GLASSEYE
Another one, if you can find it, is the Denver Gentleman's first CD, "Introducing..." I think it was re-released so it may not be hard to find any more.
You also might look into HUMANWINE and the World Inferno Friendship Society - although my experience with them is pretty slim, they seem to have all the same fans as the Dresden Dolls...