According to some folks I know in a picturesque Swiss valley, the panel is manufactured by Comtronic
http://www.comtronic-gmbh.de/en/produkte.html
Not sure if the switches themselves are sourced from someone else or not, but Pilatus buys as an assembly.
If I find out more I'll let you know.
Are there circuit breakers for each of these switched circuits?
They look a lot like the old "Mooney" switch, which was actually a breaker and switch in one unit. As I recall they were made in Germany and cost $80 or each.