thanks, interesting article but it just reinforces my belief that there isn't clean solution to be had from a deisel engine. By clean, I mean easy to obtain and run.
Since this is for only occasional usage, I am less concerned about pollution and far more about reliability and low(er) maintenance requirements. The focus on NG is to avoid having to treat and/or manage a liquid fuel. It looks like a gasoline engine conversion is the best bet. I'd still have to deal with oil changes but that's probably acceptable. Especially if the controller can remind me when it's needed.
Interestingly enough, a very large part of the installation cost will be the transfer panel and associated wiring. This is due to the complexity of my site wiring.