From my research in Diesel TM's to run in a Sprinter I came out pretty disappointed. All of the machines available by the big guys are expensive and outdated compared to the newer gas models, they also have a lot of vibration which could cause some problems. They are also substantially more expensive than gas. I believe I have seen a PTO set up in an Isuzu that wasn't a Vortex but can't think of it at the time will post again if I do.
Ultimately I decided to have a separate tank mounted and that really has been a good way to go, but if you go that way just make sure to have it done by a good fabricator and mounted in a position easy to refill.