General logic looks fine. Most of my comments have to do with documentation and ensuring consistency.

This is missing webapi docs additions (the *.txt files, based on class names, and the addition to index.txt).

You can do a 'make html' to see that the docs look right.

I still think that a class is going to be better than a dictionary, so that it's easy to look at one definition and know all the possible values. It's an interface all implementations must follow. I don't think a dictionary communicates any of this well.

Can we factor this out into a common function?

I think it'd be worth adding a new _api_get function that does the http_get, simplejson.loads, and try/except. Callers could then just call that and deal immediately with the result.

I think we need docstrings that detail what these do and what's the format of the results.

Should add docs here too.

Missing period.

Can you add constants for this and the other cache key?

We have this function, but then we build cache keys inline in the other functions. Any reason we don't just go with one way or the other?

The """ should be on the next line.

Missing period.

Is there any standard in terms of what the limit is per call? Can the get_commits functions take one, or do some services impose a cap?

The """ should be on the next line.

Also, the webapi docs should be more explicit about what the caller should expect. Right now, there's nothing showing what the caller will get back from this API. I want to make sure any new APIs we add have detailed docs.

Same applies to the commits below.

""" on the next line.

Trailing period.

This would read better by doing 'for commit in commits', and then accessing commit instead of commits[i].

This looks great. I have only a couple small comments, but I don't need to re-review it once those are taken care of.

Should inherit from object.

Should inherit from object.

Just noticed, the "trunk, _" and similar below overwrite the ugettext alias "_" in this scope. We should probably avoid that, in case it bites us later.