You may take a look at Parallel-port Two-axis PWM servo controller for Etch CNC
It uses two simple DC-Servo connected to a PWM bridge and encoders. All connected directly to the parallel port.
You did not write anything about home or reference switches (and limit switches...)? Hope your design has one (at least).
Without any real knowledge about tube benders (except they bend tubes...) i would mount a reference or home switch at a (slightly) negative angle (-5°) to leave some space when inserting the tubes...
EDIT: The config files are there, too. So you can have a look at them.