I'm in the same boat. I did a crude theme for 0.2 but the presentation code has changed some much in 03-s that I'll have to start again form scratch.
Supposedly Theme/Skin documentation was part of 0.3 according to the roadmap and the website, but it's nowhere to be found. I've asked the developer and user mailing lists and nobody will reply. Guess the answer is no.
I still want to create a theme, but I see two major roadblocks:
1. It's still a beta product and there may be still lots of changes to the html/css code that would render my theme obsolete in any future version.
2. The way the template system works it seems counter-intuitive. I find myself having to override a whole bunch of css across multiple files when a single css file would make it a lot easier to manage. Specially for things that are almost identical in presentation.
It's a lot of work if you want to do anything beyond changing colors, fonts and graphics. Any layout changes, and you're in for some real work.