Knaack Manufacturing, through its Weatherguard product line, has a van fitment guide on its website that allows you to see which of its products mounts where and how to integrate them all together. However, with that said, as great as the Internet is, you should also make contact with the manufacturer and talk with a representative from any and all companies you have any interest in. Their insight and knowledge will be invaluable in helping you design you van. More than just individual parts they are separate modules that are designed to work together. As such, you should stay with one manufacturer when assembling your van.
Cabinets come in a variety of styles and sizes.
You can even get some compartments foam lined to protect any fragile tools or equipment. Drawer bin units are another item worthy of consideration. These units allow easy storage of small parts and all offer moveable dividers to allow the customer to rearrange or accommodate different types of materials. Floor drawers are also extremely useful. Mounted on the rear floor of the van, these drawers are available in a variety of versions and slide out to allow easy working access.