Two ideas for an entrepreneur - I may do them myself, but not soon.
1. A plate that mounts to the left Tourfella rack for mounting one or two tool tubes in the open space between the rack and the wheel.
2. A toolbox that mounts in that space - like this one:
http://www.advdesigns.com/rurelotoforb1.html
I have sent this idea to Tourfella via aliexpress.