I make for my 4 yr old silly animals out of just about everything .. His favorites are Raindeer open face sandwiches - Bread with peanut butter, broken pieces of pretzels put on the corners of a triangle - near same size.. I use rasins for eyes ringed by a cherrios, and a small baby carrot for a nose - he pulls the pieces off anyway to eat them so its not that gross ..
And the other fav in our house is " Apple Bugs" I half an apple and core it - fill the inside with peanut butter, 4 stick pretzles pushed in the bottom for legs, 2 reg twist pretzels for wings in the peanut butter on top, I add rasins again to make lady bug dots and 2 more stick pretzels to make antenna's, raisins for eyes with a cherrio around them and one m&m for a nose.
Or make a regular sandwich but use a cookie cutter to cut out different shapes - my son enjoys doing this - but since he is the "cook" when he does he always needs to add the special ingredient " A kiss" blown on top .. I tell him to taste it to see if its right, and he always does!!
My son also loves to dip!! So I buy the individual ranch dressing packages - he will eat carrots and brocholi this way for hours .. they also have peanut butter and cheese in small containers or you can always make your own ..
Basically you can see we've tried a lot of things too!! Good luck to you! Just when you think they are going to follow along - they change course .. again!!! LOL!! Best of luck!