<<<As much as I'd like, I don't want to incur the expense and 
complexity involved in a TDI swap, but the VW Industrial 1.9 Turbo, or a 
1.9 Turbo from a Quantum sounds just right>>>>

Explore the industrial engine swap very carefully.  The VW Industrial place either won't sell it for automotive applications, or will not warranty it.  I've been told its illeagal because its not auto emmisions certified (but how could it be more polluting than the 1981 - 1982 diesel in the Vanagon right now?)  I also beieve the pump governor characteristics are different for continous load operation.

--Nate