I'm looking at my options to install tach. I did go thru the schematic and found potential source of power in the front headlight that does not require modification of the wiring. There is unused power connector that appears to be for powering front parking light (not connected in US version). It is always on with ignition on, same circuit runs rear taillight (brown wire). Second wire in the connector is ground (black with white tracer). The drawback is that this is powered also when ignition switch is in parking light mode, but not too many would use this mode anyway.
Picture below is the schematic:
This is part showing headlight with spare connector outlined red:
This is picture of the inside of headlight:
Described connector:
