Try these people....
http://www.tierferienheim-belp.ch/
This is where we board our dog when we're away and they also take care of small animals - I've seen people leave small pets like hamsters or something and I think they also handle rabbits. I think they're very nice, and we've been happy with their service.
South of Bern, just off the A6, the Rubigen-Belp exit.