I ended up building one...

Perhaps look into having something built. Find someone who does custom cabinetry and has a large, flexible shop. Some of the larger cabinet shops are set up almost like a furniture OEM, they put a lot of work through and have the latest CNC machinery. Make a sketch or a drawing. Ask what they could easily do, materials and construction techniques. Get a quote. You might find it is actually cost-effective. The quality will be top-notch and you can get something that really works for you.

Mine is huge; tall, wide, and deep. No back panel, no panels between the shelves. I have it on slides and I can pull it out easily so I can easily tweak my collection of stuff. That is hugely important. I had it painted at a local shop that refurbishes damaged and obsolete furniture from the local manufacturers.

It is a full 8 feet wide and 30 inches deep. I can fit any amplifier or receiver out there. Not to mention the always difficult center channel speaker. Total cost was less than $300.00.

jocko