Does anybody know where I get some "FLOW" diagrams for these transmissions:
4T60E; 4T65E & 4T80E???? I am trying to build shift kits for all these
transmissions. I know there is already a shift kit available for the 4T65E,
but, I want to make my own.

All the shift kit is different springs. So just find a Acrobat copy of Thrashers instructions, get the spring sizes and use those instructions and put them in yourself. I dont know if you are going to be able to find a flow diagram except in the service manual for our cars. The real one of course.

Will that work on all 3 trans? Or just the 4T65E!

The thrasher shift kit works only on the 4T65E and the 4T65-HD. The 4T60E guys are out of luck and plus the 4T60E is a really weak tranmission so shift kits are not recommended in any way shape or form.

Actually I found the flow diagrams on the US Patent & Trademark Office
http://www.uspto.gov/main/patents.htm
You'll be amazed all stuff you can find when looking at the original patent!