After about 12 images the TL slows down from 1 photo every second to... about half of that.... I thought I had done RAW TL's before but now the camera consistently slows down after the first 12 pictures..?

Jeroen, I think most digital cameras suffer from this problem with raw. If the buffer fills, then the framerate will slow down. If you don't need to shoot raw, you could either play with reduced jpegs, or easier still, shoot as video and then speed up in post. As your shooting at around 1fps, then speed up in post is probably the easiest option.

Thanks, Adrian. I guess no panning or reframing then...

Short answer, yes, the GH2 is too slow for 1 frame per second RAW. Write speeds for the GH2 is quite leisurely compared to most DSLR's.

Thanks, Adrian. I guess no panning or reframing then...

Yep, unfortunately there is that trade off. Have you looked over on the Timescapes - Digital Timelapse Discussion - Index page (http://forum.timescapes.org/phpBB3/index.php) forum? It might not answer your question on the GH2 specifically, but there is plenty of experienced time lapse shooters there, who might point you in the right direction.