A similar company is SeaBotix [0] they have a similar [1] thruster for sale but it uses a brushed motor. They have a newer generation product (not separately listed) that uses brushless motors that has integrated motor controller so all you need to do is send it power and I2C speed commands.
For people interested in this I recommend checking out the RobotSub [2] competition. Each team releases papers allowing you to see how the whole vehicle fits together.
1 - http://www.seabotix.com/products/auv_thrusters.htm
2 - http://www.auvsifoundation.org/foundation/competitions/robos...