maybe some hope...
Yeah this is a little weird how Ford handles these throttle bodys. Most of the time it is the TPS that is bad and they do say that you must replace the whole thing together, but....
I have seen the TPS sold seperately, mostly on ebay and some other online parts stores. I have also removed my throttle body before and it looks like there is a way to pull the TPS off of it. I have a 2005 5.4.
Pull your TB off and check it out if you haven't already. Mine has a little screw on the inside wall (if I remember correctly) and there's another screw on the outside by the sensor. It looks like you can pull those and remove the sensor.
The entire TB is 280.00 from ford, I can't remember how much I saw that sensor for, but I know it was below 100.00. The only issue you would have is to get the correct part number. But hell, it is probably printed on the old sensor.
Oh yeah, and check the wiring on the wiring harness that connects to your tps. I found on my truck a few different places where the wiring melted because it came too close to the engine and some shmuck that worked on or owned my truck before me didn't replace the harness brackets or holddown thingys.