It will ruin the frackin' game
nice to see another BSG fan here, too 
besides, i agree with him:
one might consider the option of stealing/duplicating (ship) techs when all the available races in a game have at least more or less the same tech tree(s), but since this is not the case, i´d basically not support this.
the idea itself is interesting, but not in a game like SOASE.
the climax of all should be a temporary control, but not the capability of building otherwise unavailable units, except for maybe extremely high tech levels (7 or 8).
besides from all what was said here, it might be an interesting idea to share technology that has nothing to do with ship (construction).
you know. like the TEC and vasari (in the way of true diplomacy 
) exchanging tech to optimize the yield of mines, etc.
perhaps a treaty/researchable tech in which both/all players must invest a (rarely high) amount of resources to raise their income by a certain amount as long as they participate in the treaty.
