Wallrun.tbm is easy to make , pretty much there are 4 wallls and a ceiling ( and a door i think). Those are completely transparent ( invisible), now there are very thin black objects that outline the entire thing .
TRichard's Tip : just because when you see the size or position in worldbulider , it doesnt mean you can adjust it even more .
Ex: katana.tbm - the thinest you can make an object in WB is 0.0625 BUT If you look at the mod in notepad , the object that is the blalde width is smaller. So to make somthing very thin , you just have to decrease the decimal ( 0.05, 0.04,0.03, ect)
This goes for just about every setting for an object or body part , play around with it.
There is a bigger wallrun mod , I beleive its called Dojoroom .