Yes. There are multiple UI projects that build on the WinUI 3 components in the Win App SDK.
There's the first party MAUI which is an updated version of Xamarin Forms. The two best-known third-party implementations are AvaloniaUI and Uno. I prefer Uno, it has more cross-platform targets.
There's a fair bit of detail in the recently released Moonbase Alpha Technical Operations Manual, one of a series of in-universe documents from various Anderson shows.
What was called Shadow RAM on the BBC Micro was a bit different to what's described here - it was a technique to have display memory to be paged outside the normal memory map to allow more space for programs.
I think what you're describing might actually be what the Acorn 8-bit world called "sideways ROM/RAM" - the 16K between 0x8000 and 0xbfff was paged and different ROMs (or RAM, if you had the right add-on hardware) could be selected to select different pieces of utility/system software (eg filing systems and BASIC).
However, at least one peripheral I'm aware of for the BBC Micro did do the "copy ROM code to RAM then page out the ROM" trick this is talking about. The 6502 second processor had a small ROM containing startup and basic OS code. The hardware passes writes through to the RAM either way but there's a latch which initially puts reads through to ROM. The first thing that ROM does on reset is copy itself into RAM - you can see the original source code which was recently discovered in GitHub[0]. I'm not quite sure why it did this though.
Two things for me. An electromagnetics finite element analysis package that was then used to design the actuators for the landing gear for the 737NG-series; where millions of people’s lives have depended on that landing gear working. And the coupling filters for the HF amplifiers in the Australian over-the-horizon radar array.
In all these I was only part of the project, but everyone’s work added up.
Amusing to see that the last line of the piece refers to "sci-fi on speed", as amphetamines were the drug of choice for the spiritual forefather of the movement, Philip K Dick...
There's the first party MAUI which is an updated version of Xamarin Forms. The two best-known third-party implementations are AvaloniaUI and Uno. I prefer Uno, it has more cross-platform targets.