has anyone used this battery yet? The Ofeely New 11.1v 6000mah, Anyone know if this is supported by DJI?

3rd party batteries are not supported by DJI. Using them might even void your warranty.

Those things aside, this is the only 3rd party battery I would consider using:
http://www.amazon.com/gp/product ... Id=MVODXBWRLSRHLYCR

Limefuel also makes a 6000 mAh version, but it's been on backorder for a long time.