The 47rh has a 23 spline output, like most 80's-up Jeep transfer cases. Try several of the adapter companies for a Jeep T-5, AX-15, or similar transmission to a Dana 20. The bolt patterns and splines are the same (Dodge/later Jeep), although the depth of the centering ring varies. That can be easily dealt with.
I called Advance Adapter and they can adapter their dodge nv4500 to d20 kit that will work with 47rh/re. You need to let them know the length of the output shaft from od housing to make sure the adapter sits flush with the end of the shaft. They have both 23 and 29 spline kit, 50-0209/23 spline. FYI.