I saw ArtNet running native on a MAC at LDI, i did called SandSys, and they told me 2 things, 1st they are working to release a MAC version, anmd 2nd they are working a product to connect Catalyst using Sand Boxes and Artnet.
SandNet is great, i have 2 UMX4 boxes, and very happy with those, use with Wysiwyg.. etc... Shows the DMX lines, and other stuff, but to connect the Catalyst or PixelMad, Sand products will need a third software, is not a direct conection like the CIBs and ArtNet devices. But definitly works great.
Wait to see the MAC SandNet