Why would it be a bugger to convert to RWD, that's how they come from the factory? These engines aren't mounted east-west & have never been available in a front wheel drive version.
That was the 3VZ in the Camry/Avalon.
Have you tried looking up E-bay for a supercharger?
There are a million of them going 2nd hand in the US.
I'm trying to find one for a 1MZ-FE, which are really rare.
Search for Toyota Supercharger in the Completed Listings section to get an idea how much.
There is currently a whole engine with supercharger going for US$2700.
By the time you add in custom turbo manifolds, etc, I think you'd go over this kind of price.
Don't forget that the supercharger kit comes with everything (boost controller, 7th injector if needed, piggyback computer)