I can't do CLL because my inseam (32) is already very long for my height (172 cm). Torso lengthening would be the only viable alternative, but I can't even think of a way to do it. We know that NASA astronauts can grow up to 2 inches in space, so this is probably the limit for it. How would you lengthen the spine in a permanent way? Injections into the disks to increase collagen will make you taller, this has been done with seniors who have lost material in their disks, however the spine might not be able to handle that much collagen in the disk under gravity. You would probably have to go back for more injections as this might not be permanent. Another more permanent method would be to graft bone discs in between the vertebrae columns and the collagen, this is done in spinal fusion surgery. If done across all the disks you could expect a 2 inch increase in height. However it would be a nightmare to do that operation as its nearly logistically impossible, as there are 24 non fused columns, which means that you would have to insert these disks 40 something times into the spine. I would expect a rotating team of (non ethical) surgeons to do this. This is just a thought experiment so if you think I sound crazy I'm not, I'm just thinking here. Finally, you could perhaps insert a rod that would push up the spine in a way to stretch it out a few inches, which is done in scoliosis patients. All of these theories are just pie in the sky dreams for me, but maybe there's a simpler way to achieve increase permanent spine length that I haven't thought about,