i'll probably look closer at this sometime, but one initial comment:
   
   syncing disks... simple_lock: locking against myself
   lock: 0xf034d5ac, currently at: 
   /amd/halloran/r0/d2/NetBSD/src/sys/kern/kern_synch.c:1237
   on CPU 0 last locked: 
   /amd/halloran/r0/d2/NetBSD/src/sys/kern/sys_generic.c:1133
   last unlocked: /amd/halloran/r0/d2/NetBSD/src/sys/kern/kern_synch.c:744
   
   pool_get(PR_WAITOK) with held simple_lock 0xf5742c68 CPU 0 
   /amd/halloran/r0/d2/NetBSD/src/sys/kern/tty.c:2487
   
   pool_get(PR_WAITOK) with held simple_lock 0xf5742c68 CPU 0 
   /amd/halloran/r0/d2/NetBSD/src/sys/kern/tty.c:2487
   
   switching with held simple_lock 0xf5742c68 CPU 0 
   /amd/halloran/r0/d2/NetBSD/src/sys/kern/tty.c:2487
   xcall(cpu1,0xf00087e4): couldn't ping cpus:
   ----- end panic message -----
   
   The files refereced are (obviously) on my file server, which the failing
   machine accesses via NFS (via 'amd').

these references are the source files of the kernel build you are
running and are no longer active.  they are hard coded strings in
your kernel binary...


.mrg.