I have a very deep front sump pan, which is why I'm looking into rear steer.
The Wilwood Pro spindles claim to be interchangeable from side to side. No mention of Ackerman. This is another reason that leads me to believe it is not an issue.
http://www.wilwood.com/Spindles/SpindleList.aspx
I do like the Panther frontends, but they are a little on the wide side for the AD trucks. The 55 and newer trucks are a different story.