[Marty Ward]

I think it is a great idea. Not only could you have separate techs but separate buildings as well. What this would give you is a dynamic that is missing, unbalance. Right now everyone can get the same stuff, except the special traits and their is not tremendously different than the standard stuff.
What IF your race could research shield 10 but couldn't develop a weapon to save it's butt. What if your race started out with a lot of techs but had terrible research ability.
There would be a great incentive to keep alliances and trade, espescially if trade or giving techs was limited to having a high treaty.
Unfortunately it probably would be a major pain in the butt to set up and test. There may also be a limit in the program for this.
Great idea though!