Both the Audiovox 8910 (on Pocket) and the UTStarCom (CricKet, MetroPCS, maybe Pocket sometime) are on unlimited carriers. Here are my reviews for them, with the 8910 on Pocket and the 7025 actually on Sprint (same phone across carriers though, just different extras and different color).
Note, however, that my opinions on the 8910 have changed for the worse since my review; it turned out to be a phone that didn't have an address bar on the browser, and no bookmarks either, plus the "2" key went out after abobut two months of usage. Hence my conversion to the Motorola v323i...which I'll review soon...but for now, take a look at these reviews, taken from Go4Prepaid's phone reviews section...
UTStarCom CDM 7025