The 1600 KV 70mm sounds like it's what you're looking for. I'm not sure how long 2300 mAH will last you, but if you keep the 15T pinion on there you should be able to keep amp draws down. That motor is rated to pull up to 102 amps burst and 85 continuous, but with the voltage you're running I'm not sure that it will hit that kind of amp draw. In theory, with the rated wattage of the motor and the voltage you're putting to it you should be getting around 47.6 amps but don't take my word for it. If you can keep the amp draw down, that 7s1p pack should last you 15 minutes or better. If you don't mind going lipo, a 5s-6s 5000 mAH lipo might do you a little better.
No idea when they're shipping, I got my order in fairly early so I'm hoping to get mine before the white stuff is here to stay (it keeps snowing and melting, before too long it will actually stick

).
Again, I am not positive about the numbers I put above, just some quick math that works out on paper but could be completely different in the real world.