I have seen a similar question on this site but not answered correctly for my requirements. I am reasonably familiar with py2exe.
I'd like to create a program (in python and py2exe) that I can distribute to my customers which would enable them to add their own data (not code, just numbers) and redistribute as a new/amended exe for further distribution (as a single file, so my code + data). I understand this can be done with more than one file.
Is this conceptually possible without my customers installing python? I guess I'm asking how to perform the 'bundlefiles' option?
Many thanks
I think it is possible. I'm not sure how py2exe works, but I know how pyinstaller does and since both does the same it should work similiar. 
Namely, one-file flag doesn't really create one file. It looks like that for end user, but when user run app, it unpacks itself and files are stored somewhere physically. You could try to edit some source file (ie numbers.py, or data.py) and pack it again with changed data. 
I know it's not the best explanation, you have to think further on your own. I'm just showing you the possible way.
compile py2exe from executable