There are other types of TPS units out there, just finding out whether or not the ECM/PCM will ply nice with them is another story. It will also involve some rather expensive weatherpak plugs and some fabrication to work with the existing assembly, and if you have the vacuum cruise control, things get real difficult.
Rumor has it that you no longer have to buy the whole assembly. Just the sensor can be bought and calibration instructions are available. I want to say that NAPA has the sensor, but where you would source the instructions is another story.