I’ve updated my WP Unformatted plugin to be compatible with WordPress 2.1 (and also updated the README to the new format). Thanks to DF for letting me know about the incompatibility.
The download is available on my WordPress Plugins page.
If you have any trouble with this, please open a thread in the WP Support Forums and send me the link.
Alex, do you happen to know if it is possible to pass the custom field ‘sponge’ setting via an XML-RPC call? I’m using the Text Control plug in and would be interested in another solution that allows me to post css style tags in my html coded XML-RPC posts.