The 3.4.0 ebuild should work Reproducible: Always
What does 3.4.0 have to do with adding a live ebuild?
The live ebuild will be much like the 3.4.0 ebuild.
dev-lang/python needs many patches and changes in them are sometimes needed. You can use properly tested, regularly updated (once per week) snapshots of dev-lang/python provided in Progress Overlay.
Note that use of the Progress Overlay is not supported by the python team.
For now, we don't want to maintain a live ebuild for python.