I am considering building in walls for my HT room for a number of aesthetic and practical reasons. Most commercial offerings, even most of the best, don't include an enclosure, which gives a number of potential problems (unpredictable bass response, rattles, etc.). Those that do are often cost prohibitive (such as those from Triad).
So, I am considering the DIY route. One strong contender is using a variation of the Hiddenite, due to its friendly impedance (my Yamaha YPAO receiver needs 6-8 ohms) and low cost, and excellent off-axis response.
Other alternatives might include the Tanzanite or SA-1, because the limited narrow vertical dispersion would be fine for a seated position in the room typically, and might actually make the roon easier to tune.
I will simultaneously be installing sound treatment panels/bass traps. Use of an adjacent attic will allow unrestricted cabinet depth, at least for the center and L/R, and also a corner loaded sub of unrestricted size.
One of the main problems I am having is finding grilles. I would like to either get perforated metal grilles like those typically found on inwalls, or some grille that would be elegant in design and could be appreciated as a visual design element in the room.
Has anyone here used any of Rick's designs in such a way? I would like to use one of these as I feel they are an excellent value.

Any recommendations or input appreciated.