crazy custom turbos like what johnny engineer suggests, if PTE would ever make it, you risk reliabiltiy issues. and often times if a turbo faills(not just seals) you risk damage of other important things. not to mention a holset/b-w/bullseyepower main shaft are different lengths and diamters than the Garrett or precision items. back plate sizes are different, compressor covers, etc. cost would add up quickly when trying to get some one off hybrid.
the 6765 is proven to work, and work well.
just like your HX35 is a proven, low cost upgrade for many, many things.