Mill power feed.

I'm looking for some advice...
The power feed on my Bridgeport clone mill has died... :-(
What remains O.K. is the initial gearing ( 1:4 ), the dog clutch, and
"safety" clutch.
My options are:
( 1 ) buy a new unit ( E-Bay shop 207 ).
( 2 ) adapt a small 3 phase motor and inverter to drive the old unit. ( inverter 80.50, scrounge motor, box, aluminium for adapter & little bits.. allow 50 ??? )
( 3 ) adapt a stepper motor to drive the old unit.
Buying a new unit is quick and easy, but a 3 phase drive would give better speed control, and might be a little bit cheaper.
The interesting option is to use a stepper motor..... this could allow computer control at a later date and is reasonably cheap and should give excellent speed control, however there is a problem :-( A big stepper motor gives a pull out torque of 220 Ncm torque, with about half that as a working output, driven in half step mode it will run at a maximum speed of 300 rpm. If I direct coupled it to the geared input it's torque output ( accounting for the gearing ) would be about 1/3rd of the standard drives 130 lb in output, and would give a maximum speed 1/3rd of the fast traverse (200 rpm ) speed of the standard drive. Gearing up gives a faster feed, but will make the torque shortfall worse, and vice versa for gearing down.
I think I need a bigger stepper motor for this use.
I would appreciate any thoughts on these options.
The mill has DRO, anyone know how to get the output of the scales to work with a CNC program... and what hardware / software would be best... the mill has to much backlash for direct stepper motor drive alone to give accurate positioning.

Barnes's theorem; for every foolproof device
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