Here is another idea...I made a invitation in the shape of s flip-flop using the Simply Summer set. I made the flip flop shape and the sun was stamped all over it, and used grosgrain ribbon to make the sandle attachment. My demonstrator did this at a class, and I loved it so much I made these invitations for my daughters birthday, which had a summer fun slumber party theme...everyone loved it!! If you want me to take a photo and email it to you send me a message and I will do so.
I also love the On the Beach set...and I am sure you could make a great card using this set as well for a Hawaiian theme....Good Luck!