I'm using sd-mmc.lbr I found by google search that has the socket outline on tPlace layer. I don't know if I'm going to be able to add the cutout on dimension layer properly, and I'm not sure if pcb makers will actually make the cutout on the pcb. For now, I just position the sd socket on the edge of the pcb. I still would like it better if I can do it like how it is done in the micro sd module picture.