Applications are totally discrete so there would be no chance of a collision (if I understand correctly).
app1
modules
mypackage1
app2
modules
mypackage2
Nothing in app1 knows about anything app2 (and vice versa).
If you don't want to maintain two copies of the same code, you could put it
in "site-packages" in the "web2py" directory. That folder is accessible by
any of your apps.
