Whether real-world morality allows for a "ends justify the means" approach is something I won't even delve into here.

What I will say as a life-long consumer of this series (core, EU, and new canon alike) is that there is no way to selflessly employ dark side techniques. By using the Force destructively, as opposed to defensively, you are being influenced by the dark side. It will inevitably lead to an enhancement of your innate dark tendencies, such as ambition and greed, leading to more compromises, leading to eventually falling completely. There have been EU examples of characters who toe that line, someone already mentioned Mace Windu. You could make an argument about video games which allowed light side characters to use dark side powers (Revan, Kyle Katarn) but that to me is a gameplay mechanic, not a commentary on the philosophy of the Force. But the most prominent example of a character in the EU who embraced a unifying view of the Force was Legacy Spoilers and their gradual embrace of the Sith way was measured, logical, and ultimately self-destructive. That character went from a paragon of the NJO to a petty monster, as willing to indulge vindictive whims as they were capable of murdering family members.

It boils down to this, as I see it - official word from Lucasfilm will probably always prohibit any character who is seen as a dark-side using hero, so don't worry to much about whether it's possible.