I honestly don't know if any of the MPX motherboards have been shown to work with the TBredBs. I have a single 2200+, and it is an inferno. It does near 2100MHz with water, but also runs around 60C diode temp! Apparently the 2400+s are a newer rev that no longer has this heat problem. I would splurge and go with 2400+ personally.
For dual motherboards, Tyan is the king of stability. If you are looking for more o/cer friendly mobo, though, I suspect that the Asus and MSI will have the best o/c features. Be aware that on the Asus you have to drill out the socket holes yourself (solder fills them). People have done this. I think the MSI board has the mounting holes and multiplier and fsb adjust, so perhaps it would be a good candidate. I have never been a huge fan of MSI, but I have not tried their dual AMD board either.
Check reviews on
www.2cpu.com for more details on MPX motherboards.