I think that, as I get older, I learn better and better how to deal with these sorts of situations. "I'm sorry, I'm really interested in a couple of other girls right now." Then name them. You can still be 'a gentleman' about it (if that's important to you) in order to either, a., not get kicked out of the club, or, b., feel like you're being a nice decent moral guy. It's about negotiation tactics, and taking EVERY other human being seriously, regardless of how they first impact you.
I actually don't mind ugly girls. Sometimes they're cool. Often you can just let them know right off, that you won't be having private dances with them because you're interested in other people (tactfully? see above). What I mind, is ugly AND annoying / bitchy / presumptuous girls. Women who demand that I pay for them even though I'm not interested in them; or who insist on regaling me with stories of how much of an asshole every guy on the planet is, for the fact that he doesn't want to pay her.
It's not REALLY the looks that are bad. It's the looks-plus-personality.
Corollary: I have come to learn that many ugly strippers are also negative about life in general, and determined to share that attitude with me.