I will be doing a single turbo conversion soon.....but it's going to be as low cost as possible (coz I don't have $4000 to spend on a T67 kit). I've got a hybrid T4 sitting in my office at the moment, old school but should be good for reasonable numbers, cerainly beats spending any money on the twins.
I have heard of a 1jz for sale in Adel wih a twin Blitz turbo kit on it if you want some big power late in the rev range....