To make a folder stand like this demands a large amount of wood. The sides as well as the back of the stand are so tall that you need two pieces of wood to create one of them.
The same goes for the three partitions, Totally you would need much more wood material to build it than you thought initially.
When it comes to joinery, you also face a problem. The mitre joints are not very strong because you cannot install keys to reinforce the joints in this circumstances. The solution is to build fence at the base around the stand to strengthen it. It adds beauty to the item as well.