Hello,
I have extensive experience with using Amazon's REST API, including ongoing daily usage to exactly the same type of information you are looking to pull.
I note that you mentioned you have tried a python wrapper, are you fixed on using python for the project? If not, I can provide a working solution in PHP, which will be portable across all systems and includes XML parsing abilities, so you can then use the returned data as required.
As part of the solution, I can build/include a proper signing process for each request and maximum request limiter to stay within Amazon's 1 request per second threshold.
If you would like to get back to me with further details on the project, I am confident we can work together to build a solution.
Thank you
Darren