Klimt: the Modern of the Modern Ketubot!
But if you were to want a custom Ketubah, in a fun (even cool or, God help me, "hipster") style, you might want to consider the Klimt aesthetic.
Klimt captures a lot of the creative and modern style, with many traditional implications as well.
Klimt and his long-gone Vienna might seem like a thing of the long-gone pre-war past -- but he is, in an odd way, the modern of the moderns, the contemporary of the contemporaries. He was cool before it was cool. Ahead of his time, with a timeless style that looks as old as it does new. We love our Klimt!