Unfortunately, high end boards are best for overclocking, and they always have SLI (well, almost always). And really, the price difference isnt huge, and even if you dont use it, its not like its gonna hurt performance elsewhere....
DFI Will probably have a boad like the Ultra-D, legendary overclocking without SLI. Again, I would recommend waiting if possible. I know its hard, but you will thank me in the end.