My daughter designed a nearly 6-ft tall Advent Calendar. We found that one must make the tree REALLY skinny or else it will be so wide it won't fit anywhere. She designed the tree and is happy with it.
This is a really awful photo, but I don't seem to have anything better.
Numbers, letters, and decorations are gold felt, with gold glitter-glue (which doesn't fall off like real glitter does).
Each pocket had to be able to hold two Matchbox cars! Pockets are "gusseted".