So I finally managed to get a vet with experience who will spay my bun. I just had to explain that in the states it was normal to spay female rabbits because of false pregnancies, cancer, and so on. There was a brief talk with the doctor and eventually he said "Ja, gut." Her appointment is on the 26th. Hopefully all will be well until then. Maybe I can even get the vet to cut her nails before the big appointment (= I just wanted to say thank you to everyone for your advice!