If you can or want to go that high, you may need to secure the leaf spring attachment points with an additional lateral frame (I did a quick search but couldn't find a link).
Most trailer suspensions are mounted on the bottom of the frame, and some lift kits are just extensions of the U mounts. I'm talking about a frame that is attached below the frame that will take the lateral forces in a turn.
Search suspension bent here and I think you will find threads on the issue.
Personally we love our 2 step entrance to the trailer!