Why not add a XML (cobertura format) output ?
I found here : https://software.sandia.gov/svn/public/tpl/coverage/branches/3.0.dev (referenced by https://software.sandia.gov/trac/acro/wiki/Development/Resources#TestCoverageAnalysis) an extended version of coverage.py module which support Cobertura output. With this XML support, we could integrate Python coverage report analysis into tools like Hudson, Sonar...
Why not add it into the main trunk ;) ? (the license seems to still be in GPL...)