DNS Server That Constantly Refreshes Cache?

[Will]

I'm looking for a DNS server that will proactively go out after a cache 
record expires and refresh its cache on its own.   The result would be a 
server with an enormous memory cache of prefetched records, which should 
always have up to date records in its cache, even when the domain has not 
been used internally for weeks or months.   Note, I'm NOT referring to a 
standard DNS server with a large cache setting.    I'm looking for a 
proactive server behavior to prefetch records whose DNS cache is reaching 
expiration.

Does such a product exist for Windows or Unix?

-- 
Will