I cannot recall the specific names of the threads but I think if you do some searching on this site you'll find several threads on alternative steering wheels and some technical information in them that might help you with your plan.

 

This should get you started'
http://www.benzworld.org/forums/unimog/1687972-1300-steering-wheel-adapter.html

 

I was thinking about the same thing only I have a 416. I guess start with spline count and diameter on the steering shaft and maybe check with let's say momo to start. They have a lot of wheel adapters. I was able to get a hub so I could adapt a custom wheel to my bronco, subaru and z. I can't see why they wouldn't have one for a mecadies that may cross over to a mog.

 

I have one of the smaller steering wheels like Krietpiel, but decided not to fit it. I had my original steering wheel covered in leather instead. If you can't find a wheel, let me know, I can sell it to you for what it cost me.

 

Similarly, if anybody wants my old boss made from the original steering wheel - drop me a line.

 

Hellgeth makes an adapter, which they sell. I changed mine using their adapter for a 1300.