Here is an install on a Heatercraft (known for quality installs on boats)
Seems a bit more powerful and robust.
George Kase (sp?) also has a semi-write up under the build section of the forum. He put it in place of the original heater which I would also like to do.
My plan would be to bring 2" hose with splitters to feed the defrost, some front directed vents, and the footwells. Control would then be via turning the vents themselves on/off and modulating the fan.