Well, a Teleportation-focuses Eladrin Fey-Warlock seems like one of the most mobile builds (from what I've heard about them). However, I was thinking you might want to look into Halflings - they get that ability to force rerolls once per encounter, I think, so that could save you. Or if you're allowed monstrous races, play a Gnome - they get that ability that lets them become invisible, and that could come in handy.

If you're going for tankiness, maybe do a multiclass Leader/Defender - that'll get you some staying power, plus the ability to use healing surges better. Don't know any specifics, yet, but you've got the books and can look it up yourself.