They might not call it an all-in-one but NAD has built an outstanding example of one.

What is the NAD M10?

The NAD M10 is – officially anyway – a ‘BluOS streaming amplifier’ which should mean it proves admirably hard to make comparison tables against as there are no other such devices on the market. If you look at the M10 for longer than a femtosecond though, it is obvious that this is an all-in-one system. In terms of the market, it is a rather important one too.
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https://www.avforums.com/reviews/nad-m10-bluos-streaming-amp-review.16561