Well, to be fair, rbarn's 300 gallon discus has been years in the making now, and there's still dozens of people following the thread, just waiting for it to update!
Sounds like an incredible project. I like how it's going into the corner, so you can see two sides. And I'd LOVE to have an office space with an aquarium to gaze into while I think
Did you decide on a sump, then? In your first post you weren't sure. I don't have any real experience with sumps, but I imagine for such a large tank, if it's built in like you're planning, a sump would be very much worth the consideration.
I look forward to watching this come together!