I've made some new contrib items that you might be interested in:
wxFoldPanelBar & wxFoldPanel
I made these things for my own use, but then realized someone else might be interested in them. They have been compiled and tested under Windows only (I don't have easy access to a Linux machine).
I think they work pretty good (at least for my purposes), but they should be independantly tested in both Windows and Linux (and whatever else).
These widgets are built as C::B project files; if you (or anyone else) is interested in them, let me know and I'll zip it all together and send it to you.