Thanks for posting this! It's exactly what I was considering when I
asked what was beneath that cover on the end of my transaxle.
Potential challenges:
1. With an offset belt / chain / gear driven setup, there will uneven loading on the bearings on the driven shaft. Enough to be a problem? Don't know.
2. That motor would be adequate in terms of power, but it's got a crummy output shaft. (Looks like a pump motor shaft.) Makes it difficult to couple to a cog to drive your belt.
This is very exciting - are you seriously considering pursuing this?