In my initial attempt to build a custom kernel according to the howto recipe published here, I boldly attempted to go from 184.108.40.206 to 2.6.22-10. Burned by that, I cautiously tried to go to 220.127.116.11, but using the vanilla source rather than source patched by debian and taking all the defaults when running make oldconfig (and in the initial stages of the build). Guess what? That worked following the recipe.
So, I now have a custom kernel. Unfortunately, this doesn't deal with the problems that are driving me to my own kernel, namely limited support for the sensors on my motherboard and my WD hard drives, both of which are too new for 18.104.22.168.
I'm guessing something changed at some point along the road to kernel 2.6.22 which requires changes to one or more utilities such as those associated with mdadm or logical volumes. So my revised question is, how modern a kernel can I use without also building my own custom utilities programs? That is, staying the utilities in etch?