So I thought about it and we really don't need a fast selection, the mouse scroll is pretty sufficient. What we do need is the ability to quickly set to your "preferred default" and the ability to set a building queue. Mainly a queue is needed so that you can do something like tell your fort to build a crane without canceling something or changing the build cycle (just stick one crane in the queue and let it end and repeat with what it was already building). Or maybe that jeep is 90% and you'd rather tell the factory to start cycling heavies after the jeep instead of canceling it.
So after 8 hours of hell because I am not a graphics designer I give, whoever you are or aren't, this -
http://zod.sourceforge.net/screenshots/production_expanded_test.png



