Nice rendering, wish I had the program and know how to do that.
Mines going to be a tempest adire alignment, I'm posting a thread with a link to it right after this.
The calculations weren't easy if you have a lot of cross bracing for a pyramid shape. Also keep in mind clearance.. My enclosure (with the 5" legs on) will be fairly easily carried in my room.
Mine will be maple laminate, with a lock mitered edge. link to my obelisk
Good luck, if you need help with calculations, frustum pyramids and cross bracing are right up my ally.
After designing it, I was looking at it, and I was thinking that I might scrap the port and make it a TL instead... Of couse thats a whole new ball game. The only problem I can see is at the top of it, its a little small and might get a little restrictive...
I like it. Go with it!!!
Try a down firing sub with a rear port or even sealed.
If you want to get real creative, make 2 and put a cool finish on them. Then get an Egyptian hieroglyphics book and engrave sayings in it like, "If you can read this you are way too smart" or "My Home Theater Rules". Put them in the corners of your HT room and let the bass begin .