Hmm - another question:  how big is your swap partition?  Mine is
   172MB, which is about 43000 pages.  That's not too far off the value
   from your panic.

it's 200MB, but i *also* have a 40MB buffer cache -- that's where
all my kmem is going, i imagine...
   
     I know I've run UVM on this system previously, so I wonder what has
   changed?


do you have a 40MB buffer cache? :-)