Is there any good way to have two keyboards, two mice, both act semi independently? That is, I want two mouse pointers, and if mouse A clicks on a window, I want keyboard A bound to that same window; same with mouse B and keyboard B (and of course they can also each click on and be bound to the same window as needed). Preferably a Linux solution, but something on Windows would be OK also.

What often happens, is someone would ask me to help them look at something, but they are multitasking multiple problems. Initially I can take over their keyboard & screen, but before long another call comes up and I have to transfer the problem / environment back to my desk, and get back to them (or end up owning the problem completely).

I think having the keyboard & pointer independence combined with an editor that lets you have multiple windows attached to the same edit buffer (like Emacs) would be wonderful.