There is a soft fibrous type one available.Right, like Eco Complete. I've looked at it and would probably use it if I ever did a heavily planted tank. I'm not sure it's less sharp than that gravel I'm looking at. It's basically a porous rock. It's not really what I want for this tank though.
I was reading about it a few months ago in a British magazine called practical fishkeeping.
They done a feature on satanoperca deamon and highly recommended it for eartheaters tanks.
I will have a look through and see if I can find out what it's called.