5box setup:
I have 4 computers, & run 5 wow accounts.

All 4 physical compueters are connected via a "Vetra VIP" hardware multiplexer.
I also have an x-keys pro & happy hacking lite keyboard per xzins suggestion in the wiki.

I run 5 clients with 1 computer handling 2 of them using keyclone.

My original plan was to use pure hardware, but keyclone worked so well, that I decided to save the money. Best $10. I ever spent.