https://github.com/websitesfortrello/classless would offer some nice designs that are easy enough to integrate into ursprung, as ursprungs html structure is very similar to what is wanted there.
Todo: Integrate those themes into ursprung by changing the html as necessary, re-structuring the css to separate those parts from default that are ursprung specific and not just styling; all while trying to work with the original classless themes (easier updates later).
https://github.com/websitesfortrello/classless would offer some nice designs that are easy enough to integrate into ursprung, as ursprungs html structure is very similar to what is wanted there.
Todo: Integrate those themes into ursprung by changing the html as necessary, re-structuring the css to separate those parts from default that are ursprung specific and not just styling; all while trying to work with the original classless themes (easier updates later).