That's some good info, there.
I guess I should also mention that I've already done a fair amount of research on the infinity engine, and read a lot of developer interviews with the Black Isle's developers about how they created their Infinity Engine games. I've also been digging around in my PS:T files using Infinity Explorer to see how various stuff works, as well. On top of that, I've downloaded GemRB, and have been looking for tutorials on how to use it to create a new game, but there's virtually no documentation or tutorials out there for doing that- at least not that I've found.
I've thought about trying to develop a prototype using CryENGINE 3 or Unity, but I'm not sure if I want to go that route or not, yet.