I haven't printed this yet, and I'm not sure it'll be useful to do so, but I figured I may as well upload everything I design to here in case I need it later. I will be building these out of 2x2 lumber (1.5x1.5) and 1/2" plywood or OSB, but I made the model in 1:25.4 scale by simply not changing the default setting from mm to in :)

Shelves final dimensions will be 5' tall, 4' wide, and 21" deep (including verticals. actual shelves are 18" deep)

edit: I printed it now, and I think the 1:25.4 scale is possibly too small to print at. 0.5mm thick shelves aren't very strong, so I damaged one of the shelves a little bit while freeing it from the support material. I don't actually have a use for tiny shelves besides "look, I printed it", so I won't be printing another copy. When I get to the workshop (hopefully this weekend) to build the real thing, I'll post that as a made one :)