A Monarch 10ee is on my dream-machine list, but in reality, a hack like that is likely what I would end up with as they are usually cheap and I'm stuborn enough to bring it back.
First off - there are 'usually' enough pull-out parts around from AC+VFD conversions that MOST OEM version of a 10EE - MG to WiaD to Module Drive - can be restored to factory as-built. The Monarch Sidney 3-Phase DC Drive & various Federal-contract workalikes are easiest of all. NEW 3-Phase DC Drives are still common, and near-as-dammit drop-ins.
Single-Phase DC Drives are not hard either. One just has honour the well-know physics, not side-track into the half-vast KB-Penta drives that were never built to handle the higher voltages needed, and the Beel/BICL contactor-reversed 1Q that can do, but falls short of factory performance for other reasons.
And then, of course, there are VFD and even servo-motor conversions.
End of the day, with so many choices a pair of "A" section vee belts can marry-up to, a 10EE is about as simple to supply motive power to as any cone-head lathe. No headstock full of worn/damaged gears, hydraulic or electric clutches....
Not
zero-effort. Not 'free as-in beer'.
But 'easy' as such things go.
Mind - having proper motive power is not the whole story.
Spindle bearings, apron innards needing wash and brush up or more, worn ways, carriage, and TS to refit. Common to ANY worn lathe, those are.
But AT LEAST there is no 12 or 18 speed cast-iron dustbin full of spur, helical, or even herringbone gears and their selectors and clutches.
"Fear not" a 10EE as a project.
They'll also do passable work with a ration of UNrepaired wear that many other lathes have a hard time matching at ANY age or state of wear.
Bill