I have an idea that divorces trades from the diplomacy screen and moves them to the unit arena. Premise: In real life (before the internet, at least), if a country wanted to give a technology to another country, they would have to take a prototype or an example piece to the other country and then explain how it worked and how it could be recreated. Even if they only traded blueprints, those blueprints would need to be physically transported to the other country somehow. Proposal: When two civs agree to trade a technology (or a lump sum of gold), a caravan unit would be created (either automatically in the capital, or by the player after the trade) and then sent like any other unit to the other civ, and then gifted. The receiving civ can then 'spend' the caravan like a Great Person, or trade the unit with a third civ. The unit could also be captured by a third party civ and either used, or ransomed (if that civ already has the containing tech), making piracy an important consideration of trading. The unit would be like a Great Person or a worker in the sense that it auto-surrenders if attacked, and so must be protected. Optional: Potentially, a similar unit could be made that follows the characteristics of the SMAC crawler unit, which is sent to another civ to establish a resource or gold/turn trade route.