Hmm..
You don't have to grow lowrider to grow small. You can if you want, but you could also just grow out something else just as well, maybe better small if you were so inclined. Just look for something that is indica dom, that you can sog and do lollipop style. I would do that before messing w/ lowrider, well, no I didn't I guess. But in hind-sight I would. Just takes careful consideration and planning. But you don't have to settle for lowrider just to get plants that take up a small area. Hell, if it's just height, you can scrog, lst, super crop, whatever. Just depends on what you want to do I guess. Good luck, you will figure it out. THe above poster mentioned clones, you could grow a short statured strain, mother it, make your own clones, run them as small as you want and get near perfect uniformity. SOG them or whatever. You got lotsa options, lowrider does not mean you will get short plants all under 15 inches.