Running two WoWs on two computers and sending keypresses to both is VERY possible. Keyclone is a very popular program for a reason -- but Keyclone isn't REQUIRED to multibox.

Hardware and "hybrid" boxers are actually quite common, though for some reason you don't tend to hear about us much. *shrug*

In any case, there are multiple ways for you to send keypresses to two machines:


You might find Bradster's hardware guide and my guide useful.