[dalke]

More completely, ħ = c = G = kB = ke = 1.

That system is mostly irrelevant for cultural and legal purposes. Even in the specific philosophical framework where getting rid of the kilogram 'absolutely essential', the current importance of the kilogram would simply migrate to the importance of the specific conversion factor to traditional units.

[Leszek]

Also known as Planck units

https://en.wikipedia.org/wiki/Planck_units

[sklogic]

Any such conversion would not need a physical object - just a set of arbitrary constants (which is fine).