But, if you (or I) were able to make a fluid-powered boiler that could run on any liquid oil product using a separate hookup, could you then assign a fuel value to 500 degree steam to consume it and make 135 degree steam? Or, would it be better (as a first mod/rough draft) to make recipes for a ...

I'd like to see a boiler that uses petroleum gas to make steam. It would have the same hookup points as the heat exchanger, but would accept a pipe for gas instead of a heat pipe.
I'd also love a recipe for turning cold steam into hot steam with heat exchangers, and an optional water-cold steam ...