what happens when you have a horizontal strip and you get to the end of a row and then you turn around and start a second row going back in the other direction?
if I understand what you mean, that won't happen. you want to have control of your uv's with this method. the way a scroll like this would work is basically the same as a old 2d hardware scroll. you set your mesh to be viewed 1 tile bigger on each side and when you scroll, you move your mesh. then when you push over an edge you reset all your uv's to the new map position and then move the mesh the opposite direction 1 tile length.