Fair enough, Mudgel, good for you to take on.
I've been pondering what to do about my Themes. As it seems that themes based on Tungsten get updated with Mercury elements when new elements are created, I'm not sure I want to maintain theme as I am not actually using them myself (but a evolution of one). Also I'm not sure anyone actually uses my re-designed Control bar. it does demonstrate the potential of theme editor well though.
Delete my purple theme (it was my first attempt and I learnt a lot making it, but it's a bit fugly)
Keep
Retro HiFi Mercury (This won't need updating unless that develop a new control bar option)
Retro HiFi Tungsten (This will grow new parts in the Mercury form)