I know that different MMOs with different Betas have done different things regarding beta characters.
For Rift in particular, the beta characters have persisted across the 6 betas -- will these characters persist after launch? Only for a privileged subset of players? (such as pre-orders / collector's editions, etc.)
Personally, I'm not optimistic, however I haven't yet found any official word from Tirion, so I thought I'd toss this out here.