The amazing Safari extension (User CSS)[http://code.grid.in.th] closest thing to [http://userstyles.org] gets on Sarari. Here is the (pimpmysafari)[http://www.pimpmysafari.com/items/User-CSS-Safari-Extension/] page.
Once I did something like cleared all local data or something and lost my User CSS stuff I made.
It's easier to back up here as gists.