I was interested in doing the same about a year ago, and it was really tough finding anyone that could do it. I contacted 4-5 different shops on as many continents and came up dry - no one wants to talk to you unless you want a minimum of 100 sets.
I finally found a place right here in TX, so will be pursuing this again. Are you wanting a R&P for your 6spd Supra diff, or other?
In my case, it's for my 6spd Supra diff, and I want to go with a lower ratio, to take advantage of the additional torque from the 1UZ. This should produce some longer 1st & 2nd gears. As it is now, 1st is nearly useless, and can only be used to get the car rolling.
Hope you have some deep pockets; IIRC we're talking in the neighborhood of $2K to $3K for a one-off custom set.
Should be cheaper if there's two of us, though.