There are a lot of threads where members talk about diesel conversions. In the past three years there have been two very good threads on the subject where a lot of photo documentation was included.
Do a search of the archives in the motorhome section and you should find what you're looking for.
We thought about it and then decided not to based on the conversion cost versus savings in fuel. Just didn't seem to be justifiable in our situation.
Air forums # 1674
1974 20' Argosy Motor Home
1974 31' Excella trailer (parting out, as of 4/1/2015 I have wheels, brake drums, windows & holding tanks left to sell)