Ideal design for a new music room

There is a comprehensive article regarding Robert Harley's experience on this topic in the latest Absolute Sound (April 2019, pp 28-40) -- quite a detailed discussion and having had my room built to the same technique (albeit with the full on glue approach) I can endorse it -- and if you have the time and skill you can do it yourself

It's a fascinating quest any way you pursue it. In my own career I've enjoyed the experience of creating many 'great rooms' with an emphasis on acoustics as well as aesthetics. A couple of the things I seem to have learned fly somewhat in the face of accepted practice as well as scientific logic (well, almost). Asymmetry is prime among these, so I was pleased to see your remarks along those lines.

Three things do stand out as universal IME: First, extended ceiling heights. Ten, twelve, fifteen feet high if you can manage it, maintained within proportion to the room's other dimensions of course. Complex, sloping planes can work very well, but need to be managed expertly. Secondly, avoid large, unbroken, continuous surfaces of any kind. Third, wood is an attractive and popular material but it's best if it's open-pore and unvarnished. I've seen a lot of wood finished with gloss polyurethane and it's nearly as reflective as glass.

I definitely agree that the room is the single most important element in the quality of your music listening.

It's like a dream comes true. One thing which matters a lot that its construction does not disturb your music.
Yes, make acoustic.

If anyone (other than bots) is still following this topic, you might be interested in Robert Harley's new article in TAS detailing his experiences in creating a new listening room. 

Interesting article!Having done quite a bit of diy in my home my back and arms almost ached in sympathy as he wrote about doing the ceiling.I think the cost was reasonable also.A custom built room for any type of hobby could easily cost much more in custom built ins,woodwork,and furnishings.