OK, so I've just discovered there is such a thing as 4K Cinema (no idea how I am just finding this out now...)
It also appears that 4K is a higher (projected) resolution than IMAX (which is normally 2K equivalent when projected)
Further, it seems there are at least a couple of cinemas in HK projecting in 4K
Has anyone tried it yet? I'll probably try it tomorrow for Spectre
For those wondering, I have found the following with 4K:
https://www.thegrandcinema.com.hk
首頁 - The Metroplex