Thank you for the quick feedback!

My understanding is that any subclass of VCRConnection will do, as long as its _baseclass is set to [Boto's special CertValidatingHTTPSConnection class](https://github.com/boto/boto/blob/develop/boto/https_connection.py#L82-128) and its _protocol is set to 'https'.  Such a stub is necessary because otherwise, when (the actual) CertValidatingHTTPSConnection is instantiated during a test, [the patches will not be temporarily reset](https://github.com/kevin1024/vcrpy/blob/master/vcr/stubs/__init__.py#L223-230).

Under the right conditions, a Boto module like boto.iam will eventually [instantiate a CertValidatingHTTPSConnection to use as its connection](https://github.com/boto/boto/blob/develop/boto/connection.py#L754-756).  During object initialization, [CertValidatingHTTPSConnection's \_\_init\_\_ method calls httplib.HTTPConnection's \_\_init\_\_ method](https://github.com/boto/boto/blob/develop/boto/https_connection.py#L101), passing in the CertValidatingHTTPSConnection object as the first argument.  However, since at this point the patches have not been temporarily reset, httplib.HTTPConnection is _still patched_ to be VCRHTTPConnection.  Since VCRHTTPConnection is not in the method resolution order of CertValidatingHTTPSConnection, a TypeError is raised.  If we patch CertValidatingHTTPSConnection with a stub (i.e., a subclass of VCRConnection), then the patches _will_ be temporarily reset during instantiation, and the TypeError will not be raised because httplib.HTTPConnection will refer to the actual httplib.HTTPConnection, which is as it should be when you're instantiating a real CertValidatingHTTPSConnection.

Here's why I chose to make a new stub just for boto:

- [Some of the other similar stubs use multiple inheritence](https://github.com/kevin1024/vcrpy/blob/master/vcr/stubs/requests_stubs.py#L7), but I don't think that's necessary in the case of Boto.  (As an aside, it isn't clear to me why multiple inheritence is necessary in those other stubs as long as their _baseclass is set properly.)
- The _baseclass must be set to CertValidatingHTTPSConnection in order for VCRConnection to delegate actual requests properly.  [The implementation of CertValidatingHTTPSConnection](https://github.com/boto/boto/blob/develop/boto/https_connection.py#L82-128) seems sufficiently different from [the implementation of requests.packages.urllib3.connectionpool.VerifiedHTTPSConnection](https://github.com/shazow/urllib3/blob/master/urllib3/connection.py#L132-193) (which is used as the _baseclass for the other verified HTTPS connection stubs) to justify this.  The most convenient way to set _baseclass seemed to be to create a new subclass of VCRHTTPSConnection.

If the same thing can be accomplished with an exsiting stub and you'd prefer it that way, then I'll be happy to change my pull request to do so.  Please let me know your thoughts.