Well. I stole a my girls camera at a party and took individual pictures of a P, R, O, M, a "?" and then a picture of me pointing to myself. Its not romantic but its creative, kind of fun, and not awkward at all.
I was mulling over a popular idea as well. Take her out for chinese. Have a premade fortune cookie (just get a mangled one where you can grab the fortune without cracking the cookie.) that says "the person sitting across from you whos name may or may not be (your name) wishes to go to prom with you."
so when the cookies come, offer to open hers, quickly swicth it up without her noticing and viola. romantic and creative.