This is a very simple mod for the IVAR chests of drawers currently sold (not the old school set, the new stuff most people have).
I made a filing cabinet out of two IVAR drawers and some 1/2″ birch plywood offcuts I had left over from another project. I ripped the plywood to 28cm and then crosscut two pieces at 71mm and the other two at 30cm. When assembled this creates an open ended box. I remove the bottom from one drawer and screwed the box within it with the top flush with the drawer case. Then I fit it in the cabinet so that the drawers were where they will end up when hung and fastened the box to the lower drawer with screws. The result is a filing cabinet that is easy to hang and holds a lot of files.
Notes on usage: the chest of drawers should be hung on the bottom of an IVAR unit, and the filing cabinet on the lowest two drawer slots. I was expecting to have to secure it or weight the back but in fact it’s quite stable.
Other hacks to IVAR
We shorten the sides to make table height shelves or desks (a common hack) but also we use Lee Valley adjustable feet on all our IVAR sides so that we can level them. This hack is so good it should be sold that way.