>damn, theres no way to remove this cache?

No.  This is a basic, fundamental design decision that allows 
disconnected operation.   Without the cache there is no
disconnected operation.

>I have a bunch of linux kernel developers who all have root, and I
>need better security than our current NFS.  Any ideas?

I have heard that one of the open AFS clones doesn't require
the full file in the cache.  I'm not sure of their quality

I do know solaris has ACLs on their Unix file system.  

What is the largest files you expect?

--Phil
 

-- 
Phil Nelson                       NetBSD: http://www.netbsd.org
e-mail: phil@cs.wwu.edu           Coda: http://www.coda.cs.cmu.edu
http://cs.wwu.edu/faculty/nelson