In all honesty you can't get 2x280mm rads in the front without looking at a dual bay case like the one Fractal, Caselabs and Thermaltake made. If you're looking for 2 possible mounting locations for 280mm radiators, then you can look at the Fractal Define R6, CoolerMaster H500P or the MasterCase series as well.
You didn't mention your budget, your current location and your preferred site for purchase.