If your motors are less than 30 A stall (which it sounds like they are), you could consider using a TReX dual motor controller
. It works up to 16 V and can control two independent, bidirectional DC brushed motors and one unidirectional DC brushed motor, delivering up to 30 A peak and 13 A continuous per bidirectional channel (and 15 A continuous for the unidirectional channel). The bidirectional outputs can be combined to deliver a continuous 25 A to a single bidirectional motor. Addition of heat sinks can increase the continuous current.
Out of the box it will function as a 5-channel ESC with optional channel mixing. Just plug your RC receiver channels into the channel inputs and it will drive the motors as commanded by your RC transmitter. It also has the unique feature of being able to switch between RC and serial control on the fly, allowing you to seemlessly mix autonomous and human control of the motors. When the master interface is RC or analog, input channel 5 determines which interface (serial or RC/analog) is in control of the motors. When serial is in control, the serial control source can request the values on the input channels and use them to make decisions on what to do with the motors.
Basically, the TReX should
be able to do for you what you would need two MC7 motor controllers and an RC interface unit to do, all for under $100. This, of course, depends on how much continuous current your application will require and how cool you can keep the motor driver ICs, but it sounds like you'd be able to make it work with a TReX.
To give you one idea of the scale of things this motor controller has been used to drive, you can take a look at Probotics America
, which uses the TReX to drive its RC educational robots. We will be coming out with an even higher power, higher voltage version at some point, but it's not on the immediate horizon.