Building a Class D multi-channel power amp

I am thinking of building a 7-channel and a 4-channel class D power amp. I have not done these sort of DIY products but it certainly sounds like loads of fun as long as I have clear instructions. This is what I'd like to know:-

  1. I am thinking of using Hypex modules as they seem to have a good reputation.
  2. Any suppliers on AliXpress who supply nice simple metal cases? - A standard black metal case designed for 7 channels would be nice as it can be adapted to 4 channels too. Rack-mounting brackets would be great.
  3. Is it possible to get good quality interfaces from AliXpress - XLR, speaker binding posts / Speakon, mains power?
  4. Where can I get all the internal interconnects / cables? - from Hypex?
  5. Are clear instructions available in terms of how to install the boards in the case and make all the connections?

Some people say that building a class D amp can cost as much as a new ready-made one of the same specification, any thoughts/opinions on this? - I'm sure members here who have built their own class D amps will have a good idea.

Any help, input, advice and tips will be appreciated.
 
I used to diy these but more recently I have bought a buckeye 6ch NC252 (and another on the way for fully-active HT). For me, I wouldn't learn anything assembling another class D w/switching supply kit, and so I let the guy who has his tools all laid out and a good efficient routine make a few bucks doing it 3x as fast as I could or better (no stopping for a day to figure out case grounding, etc).