I was hoping for something that could work for individual cards.
If you look at http://rigsomelight.com/devcards/#!/devdemos.defcard_api, you will see options for :frame
and :padding
and :classname
. Between those, you can make any devcard look like anything.
To be more extreme, you can totally override all CSS with this: http://rigsomelight.com/devcards/#!/devdemos.css_opt_out
That way you can make it look like anything you want.