I don't think the traditional roulette setup will work well for this, because if you don't like a band the person is just stuck with them.
A suicide pool would be the way to go. It would allow you to open the game up to more people and therefore get more bands. Depending on how many people participate, you knock out either the lowest 20% until you have 6 or 8 people left, then knockout one person per round after that, that way you keep weeding out things that aren't clicking, and you get more from bands you like. Of course you could also just take a set number of players as well, but what made my second roulette fun was that a bunch of people who don't normally participate in these did, so it was nice to get some new blood, and half of my final 6 were people I might not have thought to invite or choose otherwise.
That's the way I'd do it if you want to lock people into one band. Hell, I might do that next summer if I remember. I wouldn't want to get 8 rounds worth of a band I didn't care for.