Richy, I don't have the van system but I had a good look over the VanTainer system at the W14 Exhibition.
It is impressive, and does give good access to the various Systainers. I did feel however, that there were a few shortcomings with the system.
The van they had the system fitted to at W14 was a VW Transporter LWB van. There was a fair bit of wasted storage space behind the racking and also, as the racking is designed to be easily and quickly removed when all the storage space is required, its rigidity was questionable over a long period of time.
I'm sure it could be made more rigid for long term fitting and use, but obviously it would then take longer to remove which partly negates the idea of the system.
The quality of the fittings and the design was good, but it was quite a lot of money. They were doing a promotion at the time( not sure if the offer is still available....???) of free additional Tanos Systainers.
Hope this helps,
Regards, Tim.