Malcolm Owen at AppleInsider is reporting on a Fourth M1 chip with 12-core CPU may arrive in updated iMac Pro. This would be something above the Apple Silicon M1 Max, which is 10 core (8 core with 2 efficiency cores), so this would likely be 10 core with 2 efficiency cores. This sounds like a last M1 before M2 chips come in.
Maybe this makes the iMac Pro a bridge between the current Mac Book Pro and the Apple Silicon Mac Pro which has yet to be announced. it had seemed that the dual and maybe quad M1 Max chips rumored for the Mac Pro would also be for the iMac Pro, but this might mean it is an in between.
Let’s hope the iMac Pro has more than the current 4 Thunderbolt ports, 8 would rock, but 6 would be helpful.