Its no use to you now, but if anyone else is looking for a small diesel that will fit then a Daihatsu Charade 1 litre 3 pot IDI turbo diesel will be a good starting point. It comes with a 5 speed box and is front wheel drive.
It would actually pull the car along at a reasonable speed too (up to 80mph) and should easily get hypermiling Mpg.
I had one many years ago. It was fun
I guess you won't get one in the USA though.