The Nissan NV200 is a great little rig, and today I stumbled across a company in Southern California that makes a quality-looking conversion for it, including a poptop!
Packages range from $6000 for just the top, to $20k plus for a full Westy-style conversion. Materials are nice, and the quality of the work seems good, but I haven’t heard a lot of reviews yet. I’ll add these guys to the Poptops page once I have some more info.