This is a little old and my reply might not be relevant, but if I upgraded the hub motor on my rw4 I'd look at Grin's all-axle or the GMAC. Both are pretty pricy:
https://ebikes.ca/product-info/grin-kits.html
Grin will lace motors in a wheel for you.

I still haven't received my kit and the last communication I had with RP claimed that they hoped to get out 1000 kits by the end of May. It seems they are more likely to go out of business by then. I regret buying this bike, I don't know if I want to live with the geometry (too high of step) to do a bbshd conversion, or attempt to fit standard size rims on it. Maybe I'll get a wheel builder to take out the motor and put in a standard rear hub first.

Thanks, inoxa. I don't live in an area with a bike shop within 70 miles, but there is a nearby machine shop. It should be fairly easy to fabricate- I just realized that a regular torque arm won't work on this bike! The more I see that's unique to this bike the more I regret buying it!

I'm scared now, it seems like RP might be going out of business just as I'm trying to fix my bike! I need a torque washer for the rear axle. Does anyone know if this part can be created somehow if Rad can't be contacted? Long term I thought about replacing the hub motor with a bbshd, but not with a fairly new bike! And I still haven't received a tire kit! I'm angry!