The new phpMyAdmin (2.3.0-rc2) lets you export your database as XML

If you weren't using your database for dynamic pages (the database can't be changed online by anyone but the admin etc) then you could just make any db changes, export as XML, and upload.
The XML export isn't anything fancy, though. It formats it like so:
<db_name>
<table_name>
<field_name>Data</field_name>
</table_name>
</db_name>
Which can easily be done using a pretty simple PHP script.