Okay, I've been in touch with the nice folks at H&W, and it's looking like this purchase is never going to happen. I sent them the picture that I attached to my post #1, and from their immediate observation this is a unit that cannot reasonably be converted to a conventional knee mill. First question they asked was did it have the long bed (i.e., greater than 48"), which it does. Evidently, control end caps are either not available or non-existent for this size bed, so for starters it would require a new or reconditioned shorter one. (Not gonna happen.)
Their number 1 expert on these conversions is out on a job and will contact me when he returns, but the person I talked to was one step removed from absolutely certain a conversion could never be done on this machine without a prohibitively high expenditure of both time and money. I'll wait to hear from the expert, but H&W seems very certain that this falls into the dreaded category of what they described as 'boat anchor' (their term). I don't have a boat.
Just for clarification, I am not actively in the market for a mill. I have a very nice Vectrax with all the bells and whistles that I bought not too long ago. If I were looking for a plug-and-go machine, this one wouldn't even be on the radar screen. My main interest in this machine was: a. an enviably low cost of getting into a pristine Bridgeport, and b. having the opportunity to rebuild/modify it. Sounds like neither goal is attainable with this machine. I'm glad I initiated this post. I definitely would not have purchased this without some expert advice and no way would I be anywhere near $5K, but everyone's advice - both pro's and con's - gave invaluable information that pointed me in the right direction. H-M rules.
Regards