Only group I've seen which had a fair number of goths (as well as folks who looked like pirates) in the audience was Dead Can Dance.

They are still one of my favourite bands (seen them 3 times in Toronto - pity they seem to have broken up) and seem to have a very cross-over audience - certain tracks could be considered folky (to answer one point above) - they do The Wind that bends the Barley, for instance.

Rana