I don't have much info on making a hybrid turbo. I've tried it once using some ebizzle "TO4-ES" a friend bought and putting it on a stock turbo, and it actually worked not bad. All I did was bolt the backing plate on and install the seals and comp wheel. Didn't last long though, about 12,000kms.
What I can offer advice on, is staying away from an oil cooled center. I used to think it wasn't a problem, until I tore down a turbo (oil cooled) I ran very breifly before tossing an apex seal through it. The shaft was blue'd completely all the way up until about 3/4" behind the comp. nut. The turbo shop who rebuilt it told me if I wanted anything with decent life on a rotary to *never* use oil only - its just plain too hot to cope long term.
Whether or not you do is up to you - but that's my two cents
