Are there any plans for adding aarch64-pc-windows-gnu as a target?
One example with FOSS is that the MSYS2 clangarm64 repository is getting better each day, with more and more packages compiled for HOST mingw-w64-clang-aarch64.
But some packages depend on Rust. MSYS2 already provides a Clang built version of the Rust compiler for both x86_64 and i686, we just need the AARCH64 flavor of the Rust compiler and runtime.