I have been able to get /bin/csh loaded (the ignominy!) from init's
   singleuser prompt, and can even to type a few characters to csh, but
   the kernel vm_faults seconds afterwards with this:
   ----------------------
   vm_fault(f8190474,0,1,0) -> 5
   kernel: pagefault trap, code=0
   ----------------------
   which sends me to ddb. When I do a `ps' from ddb, I get:

If you're in DDB, why don't you type `t' and send me a stack trace?

BTW, did you do `make clean' before building a new kernel?