Hi Scott,

Lovely machine! Will be very powerful when it's finished....
The spec (large servos, turret, auto chuck, bar feed, etc) mean that it's beyond the typical scope of a hobby machine. But that's not necessarily a good reason to stop!
Converting a machine like this is not trivial, but it is entirely possible, while still satisfying your wish for modular systems which are "future proof" and replaceable.

To start though, you'll need to shake your "electronic idiot" tag! :) (I'm one too when it comes to servo control). To do this on your own you'll need to do enough research and learning to genuinely shake that tag.... For some basic DIY builds it's possible to talk people through what steps to take - yours though is a level of complexity beyond.... You'll need to do enough research to become an expert before really starting. It won't be quick, but it will be hugely satisfying...

If it were me, I'd be reading up about EMC2, and digesting some of the servo projects that people have done with it. Check out EMC2's "ladder logic" for the turret control and tool changing. If it's interesting reading, keep going... If it reads like double dutch, this lathe conversion is probably for someone else!