We actually made two of these. The bases are antique vintage sewing tables. The two I found didn't match exactly, but I actually prefer it that way. The bases can be found at many antique stores, particularly if you are looking for just the metal base without the wooden top.
To make the concrete top, you have to let go of any and all ocd. It just won't look perfect, but you'll learn to love the character. I could go on for days about what to do and what not to do. But most importantly, use the board (a laminate type board will work better because it doesn't absorb water) and the concrete mix pictured below, and make sure your concrete is super soupy. We made indentions with boards to match the sewing table base, so that the table top would sit down on the base without worrying about it tipping off. Once dry, we found sanding didn't really work to our advantage, so we made a slurry from the concrete mix and poured it over the top, smoothing it with a plastic putty knife. This helped smooth any pinholes. Once dry, we sealed it with a concrete sealer and waxed it with turtle wax for shiny protection!