Please don't limit yourself to the slow airs. I have encountered several harpers/harpists/harpies who play the fast pieces on their harps. Corrina Hewat from Scotland as well as Maggie MacInnes (daughter of Flora MacNeil) both play the reels and jigs.There is a young lady, whose name I can't recall, playing with the Bumblebees and I'm sure she's playing fast tunes more than a few times.
Here are a couple of web-sites you might want to check