Please don't do that. To your avarage linux user, nothing is more annoying then an app which doesn't adhere to standards. If you want a different look, you use another GTK theme - job done. I'm not 100% sure how it's on maemo, but I strongly suspect that there will be other themes. Please do not encourage the use of custom visuals, custom layouts or anything custom. It should be the choice of the user if he or she wants to use another style. Apart from that, both GTK and Qt are pretty flexible when it comes to different layouts.
Thanks.