If you're building the ultimate custom van, why not have the ultimate crate setup. Here's an example of a customers dream van. They wanted four crates and retain the aisle down the middle.
Crates have double windows, sprayed insides and the option of removing one top crate and replacing it with a custom storage area. Crates are mounted with a unique latching system that allows for easy removal.
For us, safety is paramount. That's why we use computer aided design and completely weld each crate.