Got your e-mail, but I have no idea what to do.

One could get a thick block of acrylic and mill out a top but I have no idea how to get the milling marks out to make it clear again. I never worked with the stuff. Fixittt uses acrylic for his Spir@l tops so he may have a better idea what it will take.
Also if the wall is 1/2" you could make a Copper top and drill some holes through the top of the walls and thread in some brass all thread, then use brass butterfly nuts or thumb screwes to tighten down the top. Copper shines up real nice aswell. You should be able to get away with up to a 1/4" hole with 1/2" walls. All you would need though is 1/8" all thread.