I know a lot of people, generally speaking not just Amigans, who don't like the old A500/600/1200 style of computer.
I would go one further and say given regular computer buyers/first time computer buyers only have the option of purchasing LCD monitors and an LCD monitor on top of a desktop case doesn't work either.
It's not about getting HP or Lenovo etc to make AIO keyboards again it's about nostalgia. Having a machine that looks 99% like and you can play your favourite Amiga games on or write stuff in Blitz Basic with.
I always said this is all a fact finding exercise really, because what case you try and replicate and which OS you put on their is immaterial. The same company who would be able to make you an Amiga 1200 case would also be able to make you an Amiga 1000 or 3000 case too. I don't even own an A3000 case anyway at the moment and I would need to own at least an empty A3000 case to do technical specifications for any discussions with a case manufacturer.
Also, as it is more like a kit than a car driven away from a showroom the same ethos applies regarding the most optimistic outcome of what I may be able to offer people who share a common dream with me. I may start with an A1200 case in white with a white keyboard but there is no reason why it can not end in an A3000 case with an Amiga layout keyboard too. The skills are there it's a matter of investment over return. I can't justify building myself an Amiga 1000 alon
The cases are the first step, without this all we would have is a Mac Mini case rip-off with some free case engraving like *you know who* 
Just going to prove you don't have to be as rich as Mr BS to not cock up the Amiga project so badly and if they wanted to could have given the same effort as the C64x
Im more interested in an a500/a1200/a600 style case or the Amiga fantasy case which looks perfect.Ive heard making moulds for injection moulding is quite costly though.If you can accomplish making such a case from plastic would you consider contacting the Team Natami guys? Because this community is quite small synergy between different groups is i believe essential for many reasons.Many people are interested in Natami too so any product that could serve the needs of your project and say Natami would be mutually beneficial.A wider customer base would then be able to support your product financially and otherwise. Im more of a classic amiga fan so natami is my preferred system fingers crossed team natami succeed.
Your project interests me too and I will be following it closely I like the sound of an a1200 like case/system.