It's so obvious, it's probably been done.
I don't really care to sit in-game, waiting for someone to run Caverns of Time (okay, I can't choose that one any more at 74, which makes the sting that much worse!). But if I could sign up for LFG and have it IM me any whispers, sending, "Healz?" to my AIM or Gtalk account, I'd be all over it.
(The answer, of course, is that my freakin' comment says Boomkin. NO HEALZ. [until dual spec] Though I do off spec heal if they ask the rest of the group first.)
Does this already exist? Please say yes. And no, a guildie AIMing me doesn't count.