I have 3 360's too and always download my xbla/dlc on the kid's main console in the family room and then if I want to play the game on the 360 in my room I log on to my account on that 360. So you can get 2 consoles at a time using a digital copy that way. But that doesn't help with my daughter who has her 360 at school so I still prefer physical copies where possible.
Yeah, they can do the two console thing, the problem comes up when I am using my profile to play something else on console #3. Now with news of the delay, I will likely just buy a second digital copy.