If you're looking for great themes, I recommend Orman Clark's work: http://www.themezilla.com/ The only problem for me was that his themes are not responsive.
I've never bought a WP theme before - so it's not too hard to convert one for use in Rails? Just take the HTML, CSS, & JS and start putting it into the Rails structure? I'll seriously look into this option, then - thanks for the note.
