There appears to be not only the P800 replacement, but also the P600 replacement. In Japan the P600 replacement is called the SC-PX1V (the P800 replacement is the same plus an L at the end), but that doesn't seem so odd when in Japan the P600 is called the PX5 or something like that.
Also:
* It's not really a blue ink, more like violet from what I can tell--I bet the same violet used in the new P7570 and P9570, and it wouldn't surprise me if it's the same violet used in the "Commercial Edition" versions of the P5000, P7000, and P9000.
* Apparently, unlike the P600, its replacement the SC-PX1V will have a user-replaceable waste ink tank.
* The P600 replacement's dimensions are 20.3 x 14.5 x 7.3 inches, which is 68% the total volume of the P600.
* The P800 replacement's dimensions are 24.2 x 14.5 x 7.8 inches, which is 69% the total volume of the P800.
* The printers are supposed to be available in Japan in May 2020.
* The P600-replacement SC-PX1V is expected to start in Japan at the equivalent of about $722.
* The P800-replacement SC-PX1VL is expected to start in Japan at the equivalent of about $1353.