This quest must be fixed since the previous post. I found him just fine, Directly North of the zone in. He was indeed trackable and an easy solo for any 90.
Should change this wisp's name to Burrowing Orange Wisp. Place a tracker at 0,0 and be ready to track it when your bard/rogue zones in...It will spend a good deal under the world. This has been around how long and it's still doing this?? Then again..should we expect more from SOE? ;P