What about these electric coolant heater/circulators? They are made by Zerostart, and seem like a very cheap alternative (plus, since they heat the coolant, you would have heat immediately in the car!). Just like the Webasto, but electric instead of diesel fired.
http://www.jcwhitney.com/autoparts/ProductDisplay/s-10101/p-2473/c-10101
For 36$ for the 1000watt unit and 11$ for a 'mercedes adapter' it is still cheaper than a regular block heater, and could potentially be more effective... Might also be handy for WVO folks who use coolant to heat the fuel, since this heater would heat that fuel up too. It would be nice to just fire the engine up and switch to WVO immediately..
Thoughts?
peace,
sam