Try PCALC at www.flydma.com
It probably doesn't have your motor or battery listed, but choose a motor with the same Kv from the list and then a number of Nicads that will aproximate your lipo's same voltage at load. Most brushless motors will be about 80% efficient so it should work to get you in the ballpark.
I was looking at Neumotor ORK motors on NSP's site. They are pricey, though.
There is a chinese co that makes a multi pole inrunner too that has a cooling fan built in that maybe you should check out