Lets say I have projects x and y in brother directories: projects/x and projects/y.
There are some utility funcs common to both projects in myutils.py and some db stuff in mydbstuff.py, etc.
Those are minor common goodies, so I don't want to create a single package for them.  
Questions arise about the whereabouts of such files, possible changes to PYTHONPATH, proper way to import, etc.  
What is the 'pythonic way' to use such files?
The pythonic way is to create a single extra package for them.
Why don't you want to create a package? You can distribute this package with both projects, and the effect would be the same.
You'll never do it right for all instalation scenarios and platforms if you do it by mangling with PYTHONPATH and custom imports.
Just create another package and be done in no time.
What is the pythonic way to share common files in multiple projects?