Nice! If it does not work, you can always resell it on ebay.Well hopefully I can get this working and do the same as you are planning, make a kit that can be dropped into a Rhino.
Unfortunately I was out bid on that wrecked Grizzly. I will buy a used Grizzly front differential and actuator off eBay this week.
Edit (10 min later):
I bought it, I couldn't wait haha. I think I found a good deal, $349/diff and $99/actuator.
I do not see a huge market for the diff swap. However, if you can put together a bolt in "kit" you may at least be compensated for your time and investment.
Live axles, with aggressive tires, will really tear up a nice lawn.