I will be converting my '99 e300d over the next few weeks. I'm setting up a website that will detail how I do it, including pictures, videos and plumbing/wiring diagrams.
I'll be using 2 3-port valves, a Vegtherm, and flat-plate heat exchanger. It looks like I'll make my own tank.
I've posted some info here:
http://biodiesel.infopop.cc/eve/forums/a/tpc/f/159605551/m/3751001422
When I have my site up, I'll start a new thread.
I think we'll see lots of e300d's being converted over the coming months and years. They are becoming a reasonably priced used car, and they seem to be an excellent candidate for WVO/SVO.