Naming a locally-built version of a package

[Wim Lewis]

Is there a particular recommended practice for naming a locally-built package that is built with a local patch, or different configure options, etc., so that it works well with the rest of the package system, particularly dependencies and things?

Ideally: let's say I'm building a custom version of Foo-1.3. I'd like to name it such that:
   - Existing packages that require Foo will be satisfied by my patched Foo
   - Local packages which require my patched Foo can specify a dependency on it
Less important but nice:
   - pkg audit will still recognize my Foo as Foo and inform me of things I should know
   - The system won't suggest to "upgrade" my Foo to a non-patched Foo of a later version 

Is this (or a subset) possible with pkgng?