What phones an go on Alltel U Prepaid?

[chelcito]

I have the Motorola Q on an Alltel prepaid plan, I was just wondering if it is possible to put any other smart phones on it, or is the Q the only one? I've been through all of the original qwerty keyboard phones that alltel offeres (scoop, banter, freeform) So I don't want to go back to a flip lol.. I like the Q but it has a few problems and I can't turn it in to get fixed because it's not under warranty with the company