I just finished building my Dominion storage case. It was a weekend project and cost US$25 to make. I used what Home Depot calls "Hobby Wood" to build the frame. I was able to use pre-cut boards and only had to make cuts for the length and width of the case. I then was able to use some left over window blinds for the dividers. I then used some stain that I had left over and picked up 1/2 a yard of felt from Hobby Lobby. Lastly purchased hinges and a clasp to shut the case.
It currently holds all available cards and accessories for Dominion and plenty of room to spare.
The tabs I got off of BGG of course!
It is 12 1/2"D x 19.5"W. I think it turned out awesome and had room for many more expansions. The dividers are placed in slots so I can remove them for wider storage columns.