This MinimOSD board is tiny, light and very powerful.   They are a good OSD board for drones and quads large and small.  They work as standalone units and also integrate with Multiwii based flight controllers such as Cleanflight and Baseflight.  We pre-flash these with MWOSD firmware,  This means you can just wire it up and fly!

There is no better deal in an OSD out there.