Francesco,
I bought a used baby jogger on e-bay and carry all my 11x14 gear in that. I have an old suitcase that holds camera, 4 lenses, 3 holders, extension rail, dark cloth, and paraphernalia. I strap the suitcase to the jogger and away I wheel. It has large wheels, so it goes over most terrain. I have not "backpacked" with it up any mountain trails, but it performs well on paths that are not too beaten. Mine has three equal sized wheels and a front brake with a hands-free feature.
I am accorded the same respect as mothers, who here in the States rank up there with baseball and apple pie. I'm sure the burghers of Stockholm will be happy to cut you the same slack.