Went with an 8.5x20 Enclosed Cargo trailer. Plenty of room for the SS and I'm still going to do a Toy Hauler conversion myself. Already bought windows and access doors and I haven't even picked up the trailer yet. Check out this guy on YouTube - he's done almost EXACTLY what I plan on doing.
I spoke with Capt Van @ SlingThings ALLOT, but my budget vs timeline just didn't let it happen this time. However, if things change, he will be the first guy I go to again - he really is that good.