Not sure if this will help but for doing the rivets I would take and make two V notched stands say out of 2x6's or something similer. Then take a longer round post that will be about 4" longer on each side then the case your building so you can slip the cue case over the post then set it in the V notched stands so that they support it at both ends.
If you wanna get really intricate get the post leveled off on one side to give you about a 2" flat on one side the entire length then attach a flat piece of aluminum or steel, you can get the 1" wide pieces at lowes or home depot for a decent price. Or even try metal shops may be cheaper. Attach this metal strip to the flat portion that you have made.
Now you could put your rivets in, slide it into your jig and hammer away.
Just a thought. May not work as I have thought lol.