It depends on what type of motor you are looking for. To purchase a motor for a boat you can visit boatmotors.com. A 75 horsepower motor will run you just over $5000.
It appears that Claremont Electric Motors and AD Auto Electrics are two places that would either carry brushless motors or at least provide you with information on where you can buy brushless motors.
DORLEC tel 01246260055
One online store you can buy electric motors at is "ElectricMotors.com" They have a pretty good range of motors to choose from like jet pump, compressors, conveyors and pool motors.
As far as can be ascertained from researching this question, there are no stores where one can buy magnet motors as they are not a proven technology. One can, of course buy magnets at many stores.
any garage
you can buy hobby motors online at a store called the hobby lobby. They sell everythign for hobbies and you can find any project you would like to work on from them.
1989
Ebay motors has them.
Heavy Equipment Trader, Ebay Motors
you can maybe find a motor that size at radio shack or a replacement at ebay.com
The company Baldor is widely known as the best AC motors on the market. You can find these motors at the website www.baldor.com/products/ac_motors.asp.
try rockauto.com or your local junkyard