Not possible the frames are protected from swapping like that. Everything has to go through the trade window, which is also protected.

You also can't view inventory across accounts. All the bag mods are limited to your account.

The only way I could think of to do it would be to broadcast the contents of your inventory in a private synch channel but that would be a lot of work. Manipulating the inventory through a channel like that wouldn't work though.

You could map functions like Mr. Plow has to keys but you would still need the keys mapped on each character.