@ramones - i tweaked your capx to fit my idea of spawning as close as i could get it to act how i want it too, i think you are right about gaps.
@Rory - it seems that no matter what there will be gaps because the framerate is ALWAYS fluctuating (and therefore the gaps aren't even even). if there were some way to lock down the framerate to 60 or 30 for lower framerates, there might be a way to account for dt, otherwise nothing i can think of.
you can subtract dt * groundSpeed from the X spawn point to get them to overlap, if you use large ground pieces - heightwise - with plain cover it's not noticeable. if you are doing a platform, gap, platform, gap loop then the player won't be out these pixels and miss a jump because the gap spawned slightly to large.https://www.dropbox.com/s/n8oyndhyz10ktdv/endlessRunner.capxwretchedshark2013-02-01 02:30:55