I hit reply too quick... If the bow is too much, since it's not the "wedding" invitation, it would be just fine with out anything else. Jut cut the top border to be equal in size to the other borders.
I was thinking a flat bow would be nice. Here is a video instruction on YouTube http://www.youtube.com/watch?v=1Y58usgffLQ At the end of the video she shows show alternatives of how you can do the bows and how to place them. One option she shows has the bow in the corn at an angle with the ends tucked under the top card.
I don't think that have to be a "perfect" match. As long as it's something that you like. I'm sure no one will say "Oh her glasses and cake cutter were mis-matched"