Hey Kiwiki,
with a CNC, you would usually make this in a two-sided project with a ball nose as the last pass.
Or maybe in multiple single passes with vertical workholding?
However for router tables or hand routers, there exist bits like this Convex profile Bits or this Double Roundover Cutter Assembly with Ball Bearing. Or, for shaping/moulding machines, there exist interchangeable radius cutters for Universal cutter like this:
Felder 04.4.008 profile knive for universal cutter