I think it's not very likely. I reckon you are probably the single 1 person using CephFS and LibreELEC at the moment (maybe with an error margin, 3 persons). LibreELEC is targeted as a home theatre application, and I haven't heard of (m)any people using CephFS at their homes.
Also, the team needs extra time and effort to implement, test and support a file system that is not availabe to them in their natural habitat. Supporting a file system used so rarely will take up a disproportional amount of effort, which basically means your request is not likely to get any priority, if at all. I suggest you find a different solution to your problem.
It takes no effort to add support, simply enable CONFIG_CEPH_FS in the kernel.
Wow... here is your developer-versus-nerd situation 
Sorry guys. If only I had known it was that easy.
How do I enable that? Is the CONFIG_CEPH_FS a boot time option?
Or do I need to spin my own kernel?
You'd have to make a complete build.
We do accepts PR's.
