There are a lot...see the Wikipedia list.
As for "hot" or not, they probably wouldn't appreciate your advances if you can't appreciate their playing and only care about their looks. My [now ex] boyfriend made some snide remark about how the leader of a band I was trying out for, "Probably just wants to get with you." I mean, it's not as if I can actually PLAY or anything.

What a ****ing concept. What I'm trying to say tactfully is that I don't get why guys are still so continuously surprised to hear about "chick bassists"...it's not the Stone Age anymore! And furthermore, it's a little ridiculous for you to go on about "hooking up" with them instead of commenting on their musical abilities....what do you think this is, the Casual Encounters section of Craigslist? Come on!
For what it's worth, I didn't pick up the bass because I wanted to look cute and impress the boys. I picked it up because I thought I'd enjoy it for myself. Guess what, I was right.

If guys think I'm cute because I play bass, that's great, but I would hope to be appreciated for my abilities more than my looks. It takes me five minutes to put on makeup in the morning, wear something nice, and fix up my hair...but it takes me five HOURS A DAY to get to a level where I have some serious bass chops.
To turn this around a bit, I'll put myself in your shoes...yes, I think John Taylor of Duran Duran is incredibly attractive. But at the end of the day, I am more inspired by his skill level than his looks...and ultimately, that's a compliment to him!
I hope this makes sense. I'm not intending to flame you, I'm just trying to show a different point of view on threads like this.