"I put my version up as a cookbook recipe: http://code.activestate.com/recipes/577981-cleanupmanager-for-with-statements/"

One other idea is to model what I've done with the itertools docs by adding a recipe section.  I used it as an incubator for possible new itertools; as a set of tested cut-and-pasteable recipes; and to serve as an instructive guide for learning about how to build iterators.  A nice side benefit of posting code in the docs is that I was free to change, improve, or remove the recipes over time (the contrasts with real additions to the standard library which are hard to change once they are released).