You really don't want to go with NiMh batteries. You can get so much more power for the same weight with LiPo's. I don't know what size you are looking at, but this one is about the same capacity as the first battery in your list, at the same price and about half the weight:

http://www.hobbycity.com/hobbycity/s...0C_Lipoly_Pack

I assume that you want something bigger than this for your Kadet, but I have several of these batteries, and they work great. I get 6-8 minute flights on the Magic using this motor and a 45A ESC.

http://www.hobbycity.com/hobbycity/s...idProduct=3887

The all up weight of that plane is about 3 1/4 pounds. I suspect your Kadet is a bit heavier.

Good luck.