No, its a bog standard petrol. We've looked into diesel conversions but its a pain as the engine needs to lean over to fit which means a new sump, oil pump etc. so we gave it up. It has been done though, probably by someone in the States as they are much more popular over there.
We've never looked into LPG as we don't do enough miles for fuel to be a problem. They are however very forgiving on fuel quality, at least according to the manual, so that may be something to look into? (veg oil in a petrol.........??)
As for someone to do work, the only people we know are Shropshire Gun Bus who we bought ours from but I dont know if they only do the import side of things, it may be worth giving them a call though.
http://www.shropshiregunbus.co.uk
In my opinion the Pinzgauer knocks the spots off my 200tdi series 3 in terms of ability and engineering quality and is far more practical than my dad's 110 station wagon. The only trouble is that its left hand drive which can make turning left a T junctions a bit fun, also parts can be expensive - but then compared to a LR it hardly every goes wrong!
Sorry that wasnt much help, its nice to see another driver out there though as they're great machines.
Ric