in my research for the cause for the strange behaviour on the feeling of my front brakes, I found out that, as somebody mentioned, the ABS unit from the earlier ZZR1400 (ZX14R) is indeed interchangeable. The parameters are slightly different (given the different mass of the 2 bikes and other things) but it'll work. An Australian owner has his bike driving around like this, and I sourced a unit from a ZX14R and the vendor said that it will fit in the C14, just less efficient. I was about to pull the trigger until Kawasaki suggested to instead pull the 3 fuses of the ABS system in the bike in order to rule it out for my problem, so in the end I didn't have to go this route, but I would have done it. For some reason, the few used pumps available out there are around 350€ (380 USD) for the C14, while the ZX14R units consistently cost the half. Annoying.
BTW, my bike was destroyed last Monday (
link to the post with more details) and I might be able to get the ABS unit out of it, but I'm not sure how the insurance will see it, or how long it could take, or how expensive it'd be to ship it to the USA.