I've seen smaller crates for sale at craft stores. To me, smaller crates would be better. I could put them on a sheet of cut plywood then put wheels on it. That would make the whole thing portable and cleaning would be easier. Imagine if a drink spilled - I'd want to be able to clean quickly without dismantling the whole thing.
My DD's idea for a coffee table would be to have a table with a glass inset surrounded by a rim of cork. She says the cork would be a perfect coaster for drinks without getting the glass dirty. She is so smart.