Terry,
You wont find anything in a T series in those ratio's (4.555, 4.875) UNLESS you find a 4WD Liteace Van Wagon grey import and rob the front diff out of one of these. Yes, I said front. People I know in the US and NZ have done this for their T series rear ends. You can only use the crown wheel and pinion from the Liteace (re-build your existing T series diff around these) but unless I have it completely wrong, they came in 4.3 and 4.875 ratio's, petrol to diesel. I hav only ever seen the petrol 4WD Van Wagon over here in Perth, 4.3 ratio in that.
Cheers,
Mitch.