You could give units built in the city a special promotion that would allow them to portal a certain amount of tiles away from their current location, similar to the way the paratrooper drop works.

^^ What he said. Otherwise I think it is pretty spot on.

@JDBud, Stumpposaurus, and everyone I've been (and I am) very busy with the school and stuff. I hope to be able to work on the mod, but i'm pretty sure i can't do much until holidays. About your suggestion, it sould be nice but as i can't edit animation, doing that would mean you have a unit with "Use portal (or whatever" ability, but with the normal paratroop animation..however i (hope)'ll heep work on that. Thanks

I have a few ideas:
1- For BNW, all sea trade routes with other civilisations receive bonus science. Can receive science from sea trade routes with city-states. (reference to the Borealis)
2-Must be build in a city on or near a wheat resource.
3- I was going to suggest that it couldnt be built in the same city or civ as black mesa, but then i remembered they are two separate mods.