I did find two cliches: Betsy (though she's only a lisbian because of mental trauma) and Jimmy from Casa Madrid (though that could just be a way to get more customers.) Arcade is my favorite just because it's easy to miss the fact that he's gay, same with Veronica. I like how real they both are.
Betsy was a lisbian before she was [censored], she just got a bit more "forward" after her trauma.
Really, the way she lashed out sixually at every woman she met is no different from how a heterosixual might react- such things have been documented. It's just he happened to like girls, not guys. I thought it was a realistic portrayal, not cliche. Plus you can "cure" her of her urges, not to say "cure" her of her sixuality (as if) but get her help so she can express her sixuality in a healthy way (re: not coming on to every woman she sees).
Jimmy is a prosttute. As you said- more customers. Male prosttutes usually are supposed to act like that, no?
Also, keep in mind that having a few "cliche" characters isn't always a bad thing. Cliches usually have their basis in reality, e.g. the saying "Life is Cliche", and stereotypes usually result from the existence of people who actually fit the stereotype. The problem with cliches/tropes/stereotypes/generalizations is when you have EVERYONE fitting into them, and as we all (hopefully) know, this could not be further from the truth.
I have a friend who is a lot like Arcade, he's gay but you'd never know, because he doesn't advertise and doesn't buy into the ideal of "gay culture". He just finds men more attractive. Whatever. I also know a guy who's gay and extremely flamboyant, and fits most cliche concepts of the "gay man" that are out there.
Which of them is the "real gay"? Both of them are real- not real gays(do idealized forms exist? Ask Plato), but rather real people. I think that's the ticket here- that New Vegas treats its gay characters like people, not as "token gay dude", and their sixuality is just a part of their identity, not the defining trait.