This is a first on this forum as far as I am aware and certainly not a common issue so I would not be too concerned about it happening again. EBay or cycle salvage yards might have used replacements cheap although you may have an issue matching up the odometer which could effect resale. I believe but am not 100% certain that the same years Ninja and ER6 used the same dash.
I´ve talked to some of the after market instrument makers, and it will be quite a task to get all OEM functions working properly on an aftermarket speedo.
Will search for used european items on ebay, amazon etc.
I'm sure there are some smart people on here to help on this. I have built and arduino interface for my 08. It connects to the 4-pin Diagnostic connector under the seat. It currently displays Gear, Water temp, air intake temp, and battery voltage. This information is provided by the ECU. The ECU should also be providing all the other display functions. Here is a link to see what someone has done with information gathered from the ECU.
I have spent all of $35 us to create the display for mine. Price breakdown is 15 for color matching display, 5 for connector, 2 for arduino, 2 for interface chip, rest on misc parts and wires.
Attached file shows what information has been identified so far.