There are Micro-ATX versions of the P8P67 boards, but there are also full-size versions as well.
If you want to go with a full-size ASUS board capable of SLI and overclocking, you have some choices:
P8P67 WS Revolution
The ones you want to avoid:
Also, if you really want to overclock you should get an i7-2600K processor. The i7-2600 can only be overclocked by a very small amount.