I went to a baby shower last night and I loved this idea...Every one got a onsie and a couple of fabric markers and a piece of cardboard to put in between the material to prevent running.  You then thought of a saying and wrote it on the onsie, decorating it however you'd like.  Some ideas...Mommy's Wake Up Call, Spit Happens (on front) Then You Burp (on back), Baby (Last Name), Mommy Rocks My World (on front) Daddy Too! (on back).  It was fun! 

I think fabric paint would look nicer, it was hard to write with the markers, but it does take much longer to dry!