This is probably not going to work, or else it would have been done before..

I was wondering if you could buy Elite Banded Chests from the Auction House and open them on your Twinks to get Elite Legendaries at the desired level.

I'm guessing this is impossible, and they probably only come in L20-L21 versions, but thought I'd ask. Maybe people just don't wanna waste their chests for Twinking items.