There is another approach which may be quite cheap. Some remotes made by Universal Electronics (UEI) have setup codes which operate the Panasonic projector. The remotes are all hard button remotes, so functions like Keystone won't have a mnemonic button label, and probably you would need to print up a "cheat sheet" that lists button names that correspond to the functions.

Functions like Power or Menu and arrow buttons are programmed already, but for other functions, you would need to enter a 5 digit number (which I can supply) for each button.

Remotes include
Radio Shack RS 15-100/133/134/135 Some RS stores have closeouts of these for $1
Atlas (1054/1055/1056) remotes provided by a variety of cable companies
OneForAll URC-8820/10820
Cox 7820B

Nearly any UEI manufactured remote (So-called JP1 remotes) can be programmed if you make a JP1 interface cable, whcih you can hook up to a PC or Mac.