Well, I bit the bullet and got the new MBA home. I started the Migration Assistant from my Time Machine, and it says its going to take 14 hours (over a standard wired ethernet connection). I tried doing a straight restore from backup, but it wouldn't let me saying the backup was made on another model Mac.
EDiT: Just now checked it 5 minutes later and it says 3 hours 41 minutes. Must have been some glitch calculating time. Now I can play with it at 2am instead of 9am tomorrow.... 😀