I've found these V-brake compatible brake pads rated for carbon rims:
SwissStop RX Plus Yellow King
Trickstuff (unnamed) http://www.trickstuff.de/en/products/felgenbremsbelaege_KL.php
Paul Components (Kool Stop-based) https://paulcomp.com/shop/service-parts/rim-brake-pads/
They're all some combination of expensive, unattractive, and difficult to find.
Are there any alternatives? Or some way to use standard pads with V-brake shoes (or adapt standard shoes to V-brakes)?