I wouldn't be shocked if the Roadtrek is offered without generator. That leaves alot of space for tanks and things. From the video, it appears they are putting some big batteries in it and most of the roof is solar.
Behind the rear axle is alot of space for those batteries. Pleasureway cut thru that rear floor on their van to give access to a large battery box. Maybe that is what Roadtrek will do, but maybe multiple cuts. All your tanks will go in front of the rear axle, along each side of the van.
I think some people would go for a van without the generator. Question is, would there be a separate charging alternator under the hood? Or just solar and 110v charging?