got my hot hands on a ML 550D beta for firmware 1.0.9 and had to try the intervalometer, as it's night.
This is possibly the world's first published 550D ML timelapse, and certainly *my* first, so it's pretty rough. I think the "motion control" effect at the start was me not having the tripod locked down tightly enough - whatever it was, I left it alone and it did that itself!
The second shot is showing a lot of exposure variation. Some of this is due to my motion sensor light (and the neighbor's), but I think the rest is due to the exposure being on automatic and jumping from 5" to 10" or something. Tweaking to do there (full auto with a max iso set maybe...)
And it's as short as it is, not only because these things take ages to shoot, but because at full "L" res, you fill a card up a lot faster than with HD video!