Bantam OE's would be hard considering bantam Marans lay, so far, some poor quality egg color.
Small though - You can always find some small Araucana stock and use a breed like Penedesencas. Araucanas are naturally small, weighing around 4 lbs for hens, although I've personally had smaller, and Penedesencas are lighter in weight than Marans. F1 x F1 especially will help move more towards the Araucana compact nature and still keep a good olive color.
Speaking of which, my F1 x F! babies are growing! Looks like I've got only one pullet and a bunch of cockerels, which is fine with me. I've got two currently laying F1 pullets who need a good tufted male, and I've got 2 tufted males to choose from plus a few rumpless clean-faced, and in the mean time, plenty of food from the extras. Love OE's as dual purpose birds.