Update:
In the end, I went for the 12-drawer Sortainer over the Rack Systainer. I spent a couple of hours cleaning my existing 4-drawer and the roll-board (they were really disgusting!). This is where I'm at now:
[attachimg=1]
I still need to get a sys1 for the larger/less used hand tools (hammer, bolsters, handsaw, etc.) that will live under the cantilever toolbox.
The new sortainer:
[attachimg=2]
The drawers are labelled with a Dymo LetraTag. The 12mm wide labels are a perfect size:
[attachimg=3]
I also made a proper foam insert for the jigsaw that lives in the big drawer:
[attachimg=4]
[attachimg=5]
I still hope to get a SysRoll, but for the time being the old-style roll-board will have to do!