I’ve been working a bit on both Showcase and Speed Dial extensions. I’m prioritizing Speed Dial over Showcase, since it needs quite a lot of work. I could manage to work in a “background browser”, so now thumbnails can be refreshed. However, it will need some quality time, since I’ve to implement a non-trivial scheduling system, plus some other stuff, like a dialog to assign URLs to Speed Dial. Also, this weekend I published a new, really small, update to Speed Dial that solves conflicts with Tab Mix Plus and Mouse Gestures.
I don’t have much time lately, since I’ve just moved to another country and started a new job. So, be patient!