Okay I have to jump in and share on this one, it's just too good of a post.
I have a chopped, functional Model 8 that was built with the help of a friend from New York. Barrel length is 17" and caliber is 35Rem. I shortened the stock and she's now about 35" overall.
I too am very fond of Police versions of the Model 8 / 81.
Great topic and great website!
Cam Woodall
The Great Model 8 & 81