Flayderman's Guide shows the .44 cal New Model Army as having a 8 inch barrel while the .36 cal New Model Navy .36 had a 7 3/8 long barrel.
The New Model S/A Belt Revolver in .36 caliber had a 6 1/2 inch barrel as did the Double Action Remington-Rider .36.
The New Model Police Revolver which was a smaller gun like the Colt 1862 Police came with a 3 1/2", 4 1/2", 5 1/2" and 6 1/2 inch barrel.
By the way, even the 3 1/2 inch barreled Police Revolver retained its loading lever.
The little .31 caliber Remington New Model Pocket Revolver with the spur trigger came with a 3", 3 1/2", 4" and 4 1/2 inch barrel.
I'm sure that over the years some folks had gunsmiths (or themselves) shorten barrels but the factory didn't seem to be interested in providing their larger revolvers in short barreled configurations.