Here is a good video by Reds Flyshop that really helps to clear up the confusion on the multitude of lines out there available for Switch rods. A pretty comprehensive coverage of lines including the Wulff Ambush, RIO Scandi Short Versitip, Switch Chucker and RIO Skagit max.
*18 Jun 2015 update:
Here is a good article by Gorge Fly Shop on the various options of line for Trout Spey -
http://www.gorgeflyshops.blogspot.jp/2015/04/trout-spey-lines-no-perfect-answer.html
