I couldn't find plans for a laser cut insert for dominion storage, and figure these may be of use to someone.

The boxes were initially created using https://github.com/kigster/laser-cutter and were edited up in iDraw/Graphic.app to be what you see here.

They cut well out of 1/8 inch plywood, though did require wood glue to stay well connected. If you compare to the insert available from Broken Tokan (http://www.thebrokentoken.com/sleeved-card-game-organizer/) you'll notice that they decided to go with only 2 full width card slots. This is probably because with sleeves you are REALLY tight on room to go 3 wide. This is why the general kingdom card area has no sides. Maybe using a thinner (3/32?) plywood is a good idea, but I didn't have any on hand.

The removable card trays are plenty deep enough to hold all of the appropriate cards, and I recommend that you store them with the VP tray on the bottom, and with both open faces pointing towards the edge of your cardboard dominion box to keep cards from sliding around in transit.