Speaking from experience in audio manufacturing: It would be the WiiM Amp with 3-6dB more output, more analog outs, a worse UI, no audible improvement in quality, and it would cost 3-5x unless we could get 10,000+ people on board, maybe even if we do.
It's doable, but it would also take a year+ and occupy most of someone's free time during the year.
And there is the small matter of the software, and how to maintain it over time.
If you want an all-in one unit, a much easier route is getting a custom housing machined to hold some Hypex modules, a WiiM, and maybe an RCA splitter for your multiple sub outs. This probably sounds flippant, but there is a reason that most audio gear is either distinctly mass market or distinctly boutique. Factories generally don't get out of bed for less than 10K+ units unless you pay through the nose. They're doing you a big favor if they agree to produce less than 5K per run.