Webasto is a German company, specialized on auxiliary heaters and A/C components. That 'fire-extinguisher-shaped' thing in the second picture is the actual burner, I believe, it works basically like the furnace in your house. I also recognize the muffler in the fourth picture. Auxiliary heaters for gas or diesel engines are very popular in Europe. They make more sense than electrical block heaters or remote starters, but are quite expensive. This one looks very 'antique' to me, they built those huge things back in the 70's and 80's. I have one of those in my Westy, it's an air heater, though, not a water heater.
Check this out, but don't get too excited,
afaik they cost about 1000 bucks w/o installation.
http://www.webastoshowroom.com/blueheat/