So a number of issues have come up in the review of this feature that I'd
like to summarize here.
The first boils down to feature basically being another case of an:
http://en.wikipedia.org/wiki/Object-relational_impedance_mismatch
That is, the idea of a lookup matching against an instance in
I've implemented predicate test like functionality for Q objects.
https://code.djangoproject.com/ticket/18931
In brief, this lets you define a condition in a Q object and then test
whether a model instance matches the condition.
I believe this to be a relatively complete patch, and would
