Having seen and pondered the various attempts to preheat engines/transmissions and the pros and cons... I did some digging and came across this:
Engine Blankets & Battery Heaters - Powerblanket
Seems to me it could be a one-stop solution for not only simultaneously heating the engine and trans... but
everything underhood!
... some heat for the battery, belts, hoses, belt-driven accessories, etc. would be nice too!
I'm tempted to get one...