What would be a good overclocking motherboard (socket 775)?

I have an Intel Core 2 Duo processor and my current xfx 750i motherboard isn't helping out much when it comes to overclocking. I'm looking for something that can get me to 4.00GHz, has many (and precise) configurable settings, and that has it's northbridge/other motherboard components adequately cooled (e.g. a good heatsink on them). It should also support Crossfire (no need for SLI).
Any help would be greatly appreciated.

You want an Intel X48 (or X38) chipset for crossfire support. My Asus Rampage Formula is a good one. I run 4.0GHz on stock vcore and no added northbridge voltage.

Do you know where I could buy one of those? They're out of stock on Newegg and other sites. :/

I think your options are limited to craigslist (local pickup only!), ebay, and forums with for sale sections. The classified section here is great, but it takes time for newer members to gain access to it.