I wanted to just note that I've read Perry Metzger's suggestions for
kern.maxvnodes numbers for a few machines based on memory and tasks.
From what I understand maxvnodes can safely be set to 20-25% of 
system memory .. which in my case would be 256000 - 512000 .. The 
highest I've worked with is 65536, but I am not trying those mentioned
numbers.  I know that there is a limit for BUFCACHE which I set between
6% and %12 depending on the target.  If there are other tweakable
parameters I should be playing with, I'd be very interested.