I've been on that hunt and thanks for mentioning Punch's tool. I've used their Home Design Studio and it is a fantastic program for home design, so will look into their CAD offering as well. If their CAD software is anything like Home Design Studio, it will work well.

Google CAD for MAC and you will find more offerings like Turbo Cad which has a version for Macs. Also put Inkscape on your radar as my laser cutter uses that program on their Mac.