Hi why not try an EMAX brushless outrunner motor CF2812. I am using a CF2822, which is very similar.
It has a back mounting and being an outrunner the casing spins.
They are very light about 60 gramms, i/p volts 6 -18v up to 16 amps continuous rating. A forward only esc is very cheap and light in weight.
I replaced a good 540 motor with one of these and it worked very well as well as being much lighter and handling a much higher power output.
To have a look, get on ebay, put up brushless motors and you will see this one straight away. £7.90p including postage.
hope this helps, Roy