Can you preserve the contents of the buffer cache after an instance restart?

I know this is a problem that has faced just about every OLTP production system...After an instance restart, of course, the buffer cache is wiped out.  The result is that our OLTP system performs fairly badly for a while until the cache is re-populated.  Most of the contents of the cache is not small lookup tables but the result of transactions running through the system.  I was wondering if there is a way to preserve the contents of the buffer cache so that after a restart, it returns to it's pre-shutdown state and we don't have to suffer through the