Me thought me saw a pussycat....
No, thats not it....

I think I've read somthing about a cheat, or something, that should enable, building fences or wall's on the edges of the path tiles...

Has anyone tried it ?

yeah, its easily done

just name one of your peeps M bROOKES and you'll be able to build on the edges of paths - its much better than building to the side