I have a vacant space where a vent used to be. The setup is different because I have a cooktop on an peninsula in a sort of "U" formation. Cabinets extend over the cooktop and has everything to vent from the top. There is a partial back, made of hardwood and is the cabinet back. Behind that is the diningroom so there is no wall to find a stud for mounting. Is there an over-the-range microwave that can be mounted from the top, not requiring a wall-brace?

thanks in advance,
Wendy