No no no no Extraction is already playable. You can play it in custom games (I think some of us played it launch week, even. I know u4ix talks about playing it in customs in the last Social Skirmish). I know what Team Regicide is, I need to know if it's an option in the Regicide menu. I'm not at home, so I can't check.
If it's an option you can toggle from the menu, great. That's nifty. There were, however, people specifically asking if such a thing would be possible earlier in the thread, and that leads me to believe that it isn't possible given the tools we have now.
To me that means that 343i has access to gametypes that we don't have yet or can possibly make more gametypes and release them without issuing a title update, which means the lack of One Flag or a proper Assault variant of Grifball is inexcusable.