John,
So the real question is: Do you want functional, or do you need neat?
A rather kludgey means of adding a power knee-feed to a turret knee mill I have run across is to add a timing-drive pulley (large) to the knee handle-shaft and mount a motor and timing-drive pulley (small) to a pivot mechanisms some distance away (and out of the way). The motor is mounted on a pivot such that it can be (manually) swung to engage/disengage the timing belt. Two idler pulleys are used -- one to force the belt away from the motor to give you working "slack," and another radially sprung to engage and "lift" the belt to prevent it from hanging onto the drive pulley when disengaged.
This was a fairly common modification done to turret knee-mills back in the 60's and early-70's before power feed units became commonly commercially available here in the NW portion of the U.S. I never saw one that was "pretty," but they really were a back-saver when working with large delta-Z moves common in aerospace parts.
The manual crank handle is re-positioned to the "outside" of the (large) timing belt pulley.