Stace-Allen Model 41 Precision Chuck

[The Model A Guy]

Now that i know what this is i have contemplated its practicality and will never put it into service.
I have checked with Stace-Allen and the Model 41 is still available but only in an air operated version. Good news because the chuck jaws are available in several different sizes.
I am open to trading it for something of equal value that i can use in my shop, i.e.
Measuring tools
24” Camelback straight edge
Horizontal attachment for my BP mill
Scraping tools
or???..

 

[Toolmaker51]

Not giving up Biax scraper and/ or flaker, don't have a camelback, maybe right angle attachment, but 'or' pounds by the thousands. First off, is it flat back per brochure, backing plate or a spindle mount?
Hopefully not LOO long taper, grand spoiler of many initiatives.