@beige: As it stands, not much. We can change the background colour, choose what goes in the sidebar and change the header image. That’s it. For $14.97 (I think) per year we can have full access to the CSS for custom pimpage. I don’t know how much of the appearance is CSS and how much is WordPress PHP trickery, though.

I’ll make you an admin and you can have a look. I think you can play with the CSS and preview it without having to pay, just not make the changes stick on the main site.

EDIT: You’re now an admin. https://squadronofshame.wordpress.com/wp-admin