Ulies can and will increase length.
During Ulies, your cock is expanding in all directions from base to glans. Do one and see for yourself. Ulies make everything bigger.
I even had a germ of a thought about how Ulies can increase your length a while back. I dropped it at Thunder's and it sunk like a fucking pebble. No one cared.
Whenever I do Extreme Ulies, my flaccid stretched length increases almost immediately. In the act of grabbing the base, the pressure you apply expands the penis foward as well as outward. I also think that using a clamp at your base does something to that area, making that area easier to stretch.
I'm not sure how the length gains from Ulies compare to the length gains from jelqing, but Ulies will increase your length too. Anything more direct for length would be just flaccid stretching routines.