I think the hexagon idea was pretty good. I made some draft designs (they still need work; it's hard to fit detail into a small space):
I took the colours from the official type icons, but in retrospect that wasn't a good idea - I'll rework them later.
Opinions on this style?
Sorry for taking so long to reply, but I think the small size makes it too hard for any complicated designs. I'll stick with simpler, more obvious designs and darker lines. I'll do up some ideas later.