Automaton is a really useful addon. It will auto-sell grays, and it also has a lot of other useful functions for multiboxers (automatic repairs, decline guild invites and duel challenges, accept group invites from toons on friend list).

I think the party order issue is going to be more difficult to resolve. I'm pretty sure that even if you can get the frames to appear in the same order on each box, the unit assignments (party1, party2) and the default function key assignments to select party members will still be different. Unit frames can only change the order in which the frames are displayed.