Your choices are:
I am releasing a new set of kernels, they are not as low as the lowest kernels I produce and they are not as high as the standard voltages from Motorola (which means better battery life and more stability).
Series 1 - has 125mhz as the low end - the way 2.2 (froyo) handles wakeups has greately improved and thus 125 works well now. (This should lead to lower power consumption)
Series 2 - has 250mhz as the low end - the way 2.2 (froyo) handles wakeups has greately improved and 250 will be even more responsive but will consume more power than 125mhz.
You can get them by visiting my Kernel Page @ P3Droid Kernels.
If you like my work and wish to donate to my buy a bottle of wisky fund. Please visit here.