Anyone try cementious overlays or self leveling cement? That might give a better result than cement board products. I put down self leveling cement to cover electric radiant heat cables before putting down slate tile. I almost left it SLC because it looked so good. A nice grey concrete floor. Just mix and pour and probably a sealer or wax buff would do the trick.

Obviously there are businesses that do the overlays professionally. Not sure how expensive they are.

Here is my unfinished bathroom w/ the SLC.

I'm going to try concrete countertops for bathroom using a trowel on product over cement board next. Should be lighter and easier than pouring a 1-2inch concrete casting.