Thanks Bigfoot for a nice review. Does anyone know if Marc lets customers choose to have less options? What I mean is to build up the camper for weekending with occasional vacation instead of an "expedition" build. For example use a smaller fridge, water tank, and batteries. Does he let the customer finish off build outs themselves? Does Marc offer a shell version?
XPCamper is an evolving business so no sure answer. Every build is custom to some degree. I think a lot depends on timing, how much patience and money you have, and how interested they are in your project. Pluses for gnarly expedition mods. Deleting stuff... not so much.
For us they seemed very accommodating in the beginning and open to almost any idea, but after a year the design became relatively inflexible. Negative to a bed extension instead of under bed storage. Negative to slide out stairs in the flat bed instead of the storage tray. Negative to a small refrigerator. Negative to a custom compartment for skis although they seemed eager to figure out a way to carry an extra tire and recovery gear.
The best bet for a custom build may be the V4 cube of which there is one example. It has no cab-over which both simplifies the construction and increases design flexibility. It is intended to mount directly to a subframe, no flat bed. Supposedly it can be sized to fit any truck and the layout is up to you. I think a shell would be possible.
The V4 sounded interesting when the V2 did not work out. However, I could not get guidance from them on basic parameters such as appliance dimensions, bed and dinette options, and the best location for plumbing and electrical. It sounded like it would be a long process with an uncertain outcome. And they wanted my truck for a couple of months. You might have better results. The company may be more up to speed by now.