Diesel in the future?

So, I know my truck doesn't even run yet. but isn't the point of being in love all about thinking of the future? THATS RIGHT! I LOVE THIS TRUCK! I bought it a ring yesterday, just a bearing from my block lol. but I would like to put a diesel in it in it's later life(after I blow this engine I have in it now lol). What little diesel's would do good and fit right in this truck with little mount mods? I know nissan, mercedes, makes small diesels but have no idea what is out there. Didn't dodge make a d50 with a diesel? lol

ideas? tips? anything helps.

They did put in a 4D56 and some other ones. I would stick with gas myself. It's cheaper and parts are more available.
Just build up a second engine while killing the one you have.