Has anyone used alternative fuels in the PSD? What kind of consequences might be around the corner in durability. Will the fuel pumps/injectors process filtered veggie oil? Etc.

 

Look through the PSD threads, there are many, many threads going on this subject. Using SVO (straight veg oil) or WVO (waste veg oil) requires modification to your mule, such as a heater for the oil and other things.
SVO and WVO will void your warranty, at least that's what my owner's manual states. You cannot just dump oil in the tank.

You can run bio-diesel, as far as the warranty is concerned, it's ok.
Just read through, lots here.