Hmm. I had a play with the Chrome theme, and it's quite fun.
One thing that seems to have been forgotten is that it's actually quite easy to change the colour of action buttons etc by editing the palette. I've currently got colour 12 on the standard 16 colour palette set to 66.7R 80G 100B (CMYK=I think AACCFFFF), and I've replaced the bottom colour of tbarmidt22 with a mask, which gives everything a pleasant blue tinge.
On the subject of themes, yes, it'd be nice to have something, wouldn't it? I've added it to the riscos.info wishlist, found at [link]