I was thinking a bit about it.
I think it would be sufficient if CTransifex can generate an XML output which we could read from a backend view in our extension. It shouldn't be that hard then to write a view which lists the files from the XML in a form which calls the installer on click.
For the updateserver maybe it would be nice to have an integration for the ARS component from Akeeba. ARS supports automatically creation of the repository and also offers automatic created updatestreams. So it would be sufficient if CTransifex could put the files into the ARS directory and generates subdirectories for each release (version named like 2012.11.26.20.29 which would be compatible with version_compare). Then ARS will pick that up.
Not sure if it would work though, but I would like the idea of not inventing the wheel again