Would be great to be able to just select a solid color (similar to perhaps MailChimp color selector) as profile and user card background. Instead of having users have to find an image they like then upload. A quick/easy way to customize profile - and make it more likely users will.
In the same vein, if someone wanted to get extra with ‘auto customize’ features of the profile, they could possibly link up with ColourLovers like Twitter does for Themeleon. Since CL works traditionally with colors, this would be the spot to pull color choices from, to make it easier.