Verified answer

no, you will probably get this error:

http://www.gameshampoo.com/182675/diablo-3-disconn...

if you try

Translation:

"Has anyone (illegally) hacked the D3 beta game code to allow someone to set-up a Server on a Mac?"

Answer:

No.

The game (even the beta) *requires* you to be connected to the Blizzard servers, and if at all like the new Starcraft games, you also MUST be logged into you Blizzard account.

Good Luck!