FYI: my plans for the next version (update probably Monday) of kernel-power-settings are:
* MIN/MAX_FREQ will be specified as MHz, not KHz (possibly with backwards compatibility)
* new fields AVOID_FREQS (by default 125MHz), IGNORE_NICE_LOAD
* "kernel-settings list/save" to show or save the current settings
the kernel will change 600->599MHz and continue to ignore telephone app's request to downclock to 600.
this is hopefully the last set of noticeable changes.
Then it's up to GUI apps to modify the configuration file.

the v25 kernel does already support the "avoid frequencies" setting
http://talk.maemo.org/showpost.php?p...&postcount=227
with this you can, for example, activate only the freqs 125 500 850
or every other subset. could be please test this new feature?

thanks to everybody who's been helping in this thread.
please remember to add your answers to the wiki http://wiki.maemo.org/Overclocking