>> the successpr of the Nemo board in the works. [...] If a port to a new and expensive
>> board should be considered, then the X1000 successor sounds way more plausible.

> it has to be released first.

You don't need the release version of a mainboard to port an OS to it. A prototype or even the reference design from the CPU/SoC vendor the prototype is based on should suffice. After all, every time a board is released, it comes already with at least one OS, so the OS development/porting must have started before the board release.