Thanks Lis.
Of course I had to have a plan first and make sure the dowel and bracing would cradle the discs. This was the early concept before tweaking it a touch with a different color/graphic, and it holds 50 discs per side with about 17.5 lbs of distributed weight across the dowel rod and 37 at the middle bracing, so it's pretty sturdy for it's intended use:
I was really surprised to find those rubber end caps that fit perfectly snug over the sandwiched 1x2's that matched the casters. I had to buy a pack of 20 though, so if you know anyone looking for some 1-7/8" rubber end caps lemme know.