Haven't been over 10,000 but had to do a rate of climb test for the test program.
for interest, here are the results - I wouldn't claim my timing and my holding exactly to 65kts to be all that accurate, but it gives you the general idea!
cheers
ross
Climb Performance to 10,00ft @ 65kts
ALT Time Time interval/1000ft ROC/1000ft
1000ft Mt Beauty Airport 0
2000ft 875fpm
3000ft 750fpm
4000ft 847fpm
5000ft 826fpm
6000ft 689fpm
7000ft 584fpm
8000ft 548fpm
9000ft 523fpm
10000ft 13m15sec 485fpm