Ask HN: Extreme programming with two mice and keyboards?

Me and my co-programmer like to sit behind the same screen and work - it suits us well and is efficient. But 50% of the time, code just need to be entered/edited - meaning one of us needs to be idle, which is frustrating. What we really would like, is for each of us to have a mouse and a keyboard AND for the display manager to be able to assign windows focus independently to each developer. If we were both to focus the IDE, we would both have a cursor each, and if one of us were to focus another window, the other would continue uninterrupted in his/her window.

Googling turns up concepts such as multi-seat (which refers to two independent logins on different screens), but I can't seem to find solutions for extreme programmers.