Just an update on things that I've tried. I have set the turbo ratio limit MSR, then rebooted, but the register would get reset. I have set the MSR, put computer to sleep, and resumed, but the register would be reset. I have booted with turbo disabled, set the MSR, then enabled turbo, but there was no change in the turbo limit.
Also, desktop users who have P67 PCHs (which allow unlimited overclocking in BIOS) have the same results as me when trying to change turbo ratio limits after the system has booted.