Just a thought since your doing research anyway...
I came across a product by Sherwin-Williams called EnviroLastic. It's a coating used for bridge decks and industrial floors. It seems neat in the sense that it is elastic. The one version has 425% Elongation, +3,000 psi Tensile. It might be worth checking out. I really don't know all the details about it so maybe it won't work for a garage floor. I haven't gotten around to asking over on GJ. I didn't find anything on a search over there.
Here is some links...
The Sherwin-Williams Company : Industrial & Marine Coating Systems The Sherwin-Williams Company : Industrial & Marine Coating Systems EnviroLastic