Unfortunately, they're $100 which puts them far, far out of "pays for itself" range. It might make more sense to retrofit a block heater into the transmission.
I'm not sure I agree that it makes sense to heat the gear oil in a manual transmission, though. I don't think it takes long to get to operating temperature. It's unaffected by whether the engine is on or off. If you really wanted to deal with it as a problem, you could use a premium synthetic multi-weight gear oil. http://www.redlineoil.com/products_g...5&categoryID=6
Again, it won't pay for itself...
I already have a couple halogen lights lying around. My ex got a wicked burn off one once. Oh yeah, forgot. The garage isn't heated but it is integral to my house and has 14" thick insulated walls, although garage doors are like R-10 or something and they don't seal anywhere near as well as a normal door. The walls it shares with the house are 2x4 insulated and the ceiling has 2x6 insulation in it (above is a heated space). Never measured the temps in there before, however. The last few years have been quite warm. A while ago I got satellite TV installed one day it was -30F. I offered to let the installation guys come back another day, but they wanted to get it over with. More dedicated than I am, that's for sure.
I also need to consider the hassle of plugging and unplugging the heater. Not a huge deal if the savings were large, but convenience is worth something.
: a psychological condition or a relationship in which a person is controlled or manipulated by another who is affected with a pathological condition (as an addiction to alcohol or heroin) ; broadly : dependence on the needs of or control by another