There's nothing in the CEC spec to accommodate alpha keyboard commands, so that's a dead end. A cheap wireless keyboard and two identical receivers will probably do the trick.
A universal remote is the cheapest, easiest way to power on/off several things simultaneously. That also takes care of input switching and key group mapping. Pulse-eight is a cool device, but seems to me like an overly complex way to avoid spending 10 bucks on a universal remote.