That's a good link Zor. A pourous non-vitreous ceramic (bisqueware) is probably what you want. Any ceramic fired to the vitreous state is going to lose a lot of wicking ability. Ideally if the pores are small enough, and evenly distributed it should minimize any structural loss. However, because it's bisqueware and with added pores it will be more fragile. I think it's a wonderful idea (I've even attempted to produce a crude version of this idea, didn't work the first try, won't be the last try) and I think it will provide a semi permanent/ permanent substrate for a coil. I'm off to read the link! Me thinks their products will be far more consistent than anything I can make
There is also the potential to use a hardened vitreous ceramic composed of tiny beads, creating gaps between the beads. It would be substantially more stable, and less breakable. vary the size of the ceramic beads and it will vary the size of the gaps between them. (Like a ceramic airstone used in aquariums) the bigger the ceramic beads the bigger the gaps (more porous) The smaller the ceramic beads (particles) the smaller the gaps between them

Might take a few prototypes to work out what porosity you want. but then

you might just be golden... well you're already Golden Imeo