Could you provide link to that PEP?
As I posted in the previous message, both x86 and x86_64 python27.dll have version string "2.7-32" (shown in sys.winver). Is this right? Any of installers (x86 nor x86_64) don't create "2.7-32" subkey.

I understand that python should work without set up of sys.path from the registry, but after start of embedded python instance, sys.path don't have any valid path where 'c:\Python27x64\lib' folder resides. sys.path have ['c:\windows\system32\python27.zip', '.\Dlls', '.\Lib\'] and '.\\' expands to current application directory.
But directory is always different, not points to the python home.
When start the application which embeds x86_64 python, it just exits because can't find the 'site' module when tried to perform Py_InitializeEx(0).