Summary of response: Yay!
Oh, I mean, +1.
I am one of those who likes Python's package system quite a bit, except for the issues addressed by this PEP.
I like the simple dot-prefix proposal. We use this now in Zope 3's configuration system to refer to modules within a package. A single leading dot refers to the current package, so:
refers to the IFoo object in the interfaces module within the current package.
Additional dots refer to containing packages, so:
refers to the IFoo object in the interfaces module within the containing package of the current package.
We've never used more than two dots.
I don't really think that I've ever had problems counting up to two. I imagine that I could make it to three if pressed. ;)
I've never had problems seeing the leading dot (or dots).
I find this syntax to be simple and unobtrusive.