I'd consider doing at least one set through honest dungeon levelling. Boosting gets old fast. Why do you want 7 accounts total? It would make more sense to chain off of your original account

Old > A > B > C > D so that you can boost four toons at a time rather than three. You should earn more than enough levels this way (remember that the granted levels count as levels,if I'm remembering correctly) so after one 80


D > C 40 levels

C > B 60 levels

B > A 70 levels

You'll certainly end up with whatever you want on account A just from granted levels.