I picked up a round circular cut piece of wood from the hardware store that I use to move tiered cakes. It comes in different sized, looks like a cutting board, about an inch thick with a beveled edge and is ready to go (in the lumber section). I love it, no longer worry about moving a heavy cake.
Are you talking about one of those unfinished, small table tops that they sell at home depot? I like the idea of it having a beveled edge!
The cake drums may not seem to be any more than thick cardboard, but I assure you they are very sturdy. I've made close to 1,000 wedding cakes and always used a drum, if I wasn't using masonite. You buy masonite at a hardware store. Your cardboard circles criss crossed and taped together are not intended to provide the type of support your cake needs.
Once again, Home Depot to the rescue! lol! I always assumed masonite was some caking thing....doh!