I am not familiar with RC brushless motors: Please keep that in mind, but here is a little information that may help. A Brushless servomotor - Some Call them AC servo's some call them DC brushless motors - I call them AC Servos - has magnets on the rotor. Unlike a regular 3 phase induction motor where speed is controlled by frequency of the elctricity fed to it, AC Servos are commutated. Commutatued means that a drive feeds DC voltage into the windings, in a specific sequence such that each coil creates a magnetic field that essentially drags the rotor through its rotation. What makes the process of commutation possible, is a feedback device which communicates the electrical position of the rotor inside the stator. Concievably you could modify these RC Brushless motors, and mount an encoder, resolver or other feedback device on one end. However if you wish to use an AC drive, No magnets on the rotors will stop your project dead in the water. The problem being that DC Voltage does nothing on the windings of an induction motor.
I don't know if that helps conceptually, but I'd be willing to answer more questions, if you care to expand.