extra continent bases are in the works... they may come out sometime around the same time as multiworlds is completed. Under a typical setup there will be a penalty for these extra-continental bases, but yes.
Regarding your .5 bans, your freq caps, and your fare cap system... i've discussed most of it here:
http://www.stephenm.org/forum/viewtopic.php?p=26848#26848 (which is from page 3 of this thread). At the moment, unique world rules are not in the works in any major sense. I'm not sure i want to make multiworlds much more complex of a change then it already is on paper, at least not at the moment. I know, i know. design it in, or it's a headache later, but honestly. at the moment i've got on the plans flexibility for types of aircraft flown, length, player cap, airports present in game, continents you can base at in game, focus city cap, foreign fc cap, starting cash, starting date, potential for skill level caps, private worlds, and a few "premium only" (player-wise) worlds.
I'm open for new ideas, but flexible rules based on worlds... that's a little too big to tack on to an already gargantuan project which i'm working as hard as i can on. always more to do.