Best would be to dual wield. More killing speed, less gold spent. If you insist on gimping yourself, there are many ways you can go, but since none of those builds are about maximum efficiency (because they aren't using the most powerful abilities of the sprint/whirlwind build), don't expect much depth and useful information regarding efficiency from their corresponding guides. After all, you can try optimize any build, but in the end if you keep optimizing it you'll just end up finding yourself back into using a sprint/whirlwind build with dual-wielding. The question is how much you want to optimize vs how much you are wiling to gimp yourself, and that is not something anyone can help you with.
well even a bad skorn will net you ~ 250% crit dmg alone and a good amount of str, so it's miles better then the IK crusher. Me personally I WW w/ skorn that has lifesteal (super dumb expensive, but worth it) and I'm able to do everything from farm mp 7 to doin ubers, so it works =D
Also with a skorn like mine you can switch between builds when you feel like it. I love the HoTa build w/ the lifeleech rend to keep yourself up, and keeping the battle rage rune from WW spec so you can keep smashing things with HoTa. With my gear I get constant 900k - 1m crits with hammer and even on one target it only costs me 5 fury when I crit him ( since I get 15 back) and if there's more then 1 target I can spam that thing all day long. Also with that build I make sure to keep overpower; CA up just for the shield, and I like to use leap w/ the stun to get out of shit or start the fight.