Yes, it is, but you need to answer a few questions before you start.
1. Did you ever compile anything before? (if not, better stop)
2. Did you ever compile something via command line? (if not, better stop)
3. Did you ever compile anything in Linux? (if not, better stop)
4. Did you ever compile anything for N900? (if not, well... learn, try some simple programs to know scratchbox environment and continue)
5. Did you ever compile Linux kernel? (if not, but all previous answers were 'yes', either stop or experiment carefully, first on desktop PC maybe)
6. Did you ever compile custom Linux kernel with custom configuration? (if not, but all previous answers were 'yes', either stop or experiment carefully, first on desktop PC maybe)

If you anwered 'yes' to all above, you can download power kernel sources via apt-get in scratchbox in Linux (well, you could also download normal kernel sources, but in my oppinion power kernel is better), try to configure it to suit your needs, compile, flash, test. I cannot help you any further unfortunately and if you answered 'no' to more than 2 questions above, you shouldn't really do that now (gain some more knowledge or wait for someone other to help)