At the moment I've got two old Range Rovers outside.
One is a 3.5 Manual Vogue, near immaculate, which cost £700 on ebay The other is a 3.5 Auto Vogue, tidy, which cost £510 on ebay.
The auto very nearly has LPG. It's got the tank and most of the other bits, it just needs a bit of fettling and a few bits fitting.
Other than fuel consumption on petrol they're brilliant old things. The bits are obscenely cheap - full exhaust £106, plugs + leads £22, everything is still available by the look of things and my insurance went down from £53 a month to £4.90.