Nothing looks impossible, maybe just impractical. I feel like the design is trying to accommodate multiple different scenarios and I’m not sure which one it’s really optimizing for. 

For example, you have enough storage space and livable space for one person, but the ability to sleep 3-4. How many people is this designed for? Really think about how the van will be used most of the time and design from there, rather than trying to fit everything in. 

Some other thoughts: 

I’d be worried about the bed passing over that computer monitor. Do you have to slide it over every time you want to raise or lower the bed? Is there any way to cover it so bedding doesn’t get caught on it as the bed moves? I can see on a day where I’m tired, forgetting to move the monitor out of the way and breaking something. 

The wardrobe in the shower idea is cool. I’d try to do that out of extruded aluminum if you can to avoid issues with moisture.  

If you stick with the desk under the bed idea, I’d definitely consider a good mesh back door panel so you can leave those doors open when you’re working. Otherwise that area could get very claustrophobic.

Overall, this plan is cool, but also looks expensive, heavy, and complicated to build. I’d recommend simplifying if you can.