I used to hardware multibox in DAoC and early on in WoW using 1 wireless keyboard synched to the same channel on all computers and I know the one super cheap one I ended up using got flakey all the time with missing key strokes. It worked well enough that I never replaced them but at times it got very annoying. I would recomend getting a nice keyboard and contacting the manufacturer about buying the extra recievers. Personally if I ever went back to hardware multiboxing I would just go the vectra keyboard replicator route.