First, let me say: Bettas completely rock. when I have a house, they are going to be EVERYWHERE.

Ok. anyways.

Tiger barbs
can get up to like 3". It doesn't sound big but you will not be able to fit an appropriate size school of tigers to keep them off of the appropriate sized school of female bettas to keep them off of the barbs..... (circles, anyone?) in a 10 gallon. For the community your thinking of.... think bigger tank.

Although, I have to say that I've had many, fairly docile tiger barbs. All communities off fish will act differently, but just ONE mean guy can mess up the whole rest of the peacefull community. If he's mean enough, he can stress everyone else out and you may experience fatality.

Females can be very aggressive, and I don't know if the thought has run through your mind, but don't put a male and female together. They will most likely kill eachother.

A male can work out in a tank. The thing that sucks about a male in a community is that your options become limited- no super bright colors, no even remotely long fins. But they are beautiful, and the effort is worth it.