I looked through all my models and found my old warp pipe and ? block, so I'll probably hide them in the map as easter eggs.
I ought to create a checklist of completed stuff. I'll update it as people add content.
By the way, if you are making an image as your contribution, please make it either 16x16, 32x32, 256x256, or 512x512, so I can use them. If you want 256x512 or 1024x1024 or something, divide your image into square pieces, so I or someone else can work with them. It shouldn't be too difficult, and will ensure that your art gets featured.
Completed Stuff
o Warp Pipe - Wedge
o Question Block - Wedge
o Huge Desk - Grand Theif Fox