This can go much further than what I could do at the moment, but seeing as it can be done 5 times in a row without stopping, than I'd say this could be done forever! All you have do is be close enough to the corner from where the ground meets the wall, and notice a small sparkle of light when you do hit the wall, then right after, wall jump! This is a custom stage and might not ever be able to be done on an actual stage...I will have to test it! Take note in the thumbnail. That green sparkle below Lucario is like a "You get your UpB back"! I noticed it in the slowmo takes I did and seems 100% consistent with this theory.