The Google Doc linked below is a really powerful soloing spec that can also keep raids alive in a pinch. This is not my work, and I believe it's inspired by other work, but I'll share it with you all.
Solo Harb (61 Harbinger / 10 Chloromancer / 5 Frostkeeper)
Weissedrache@Hailol put this together for <Chaotic Potential>
With a good eternal weapon and some practice, you'll be soloing VP forts with ease (even the bosses that reflect magic).