Problems resolved

[Paul Hemans]

Thanks to everyone for all the suggestions. Here's what I did:
Stuck with sqlAlchemy because I like the idea of ORMs and I like being able 
to abstract from the database vendor.
Left the schema definitions to be generated in a separate file, so that it 
could be re-used
Dumped xml.dom and went to lxml
Brought the data processing into the main program

Works like a charm and the code is poetry.
Great community.