maybe bonesaw + breaking point, boot, 2 defense items, and clockwork? I haven't tried that build. I don't know if that would work, since we will only have 2.4 energy regen from clock work. So you would have to rely more on basic attacks than on your skills. It would be nice to know if it would work though.

I have tried it, but having focus only on attack speed will make Skaarf very squishy, yes you can max out your heroic perk really fast, but that assumes that enemy heroes just stay still, which unlikely to happen on late game. Skaarf would still need to maximize its crystal damage to reduce a significant enemy's HP. One more thing, aiming is really hard using Skaarf because skill #1 will stop on first creature/hero. This means you need a decent cooldown and some energy, at the end I am...

yep, it works really nice, but Skaarf needs to have either Eye Harvest/Frostburn first to sustain the energy, making the skills spammable enough.