> Questions:  0.  Is this whole scheme even a good idea?

Quite possibly not. Frank's point about NQNFS is exactly what I was going
to say first.  There already IS a feature that pretty much does this, as
long as both server and client are NQNFS-capable.

Second point: upgrade your network and let the server cache things.
Fast ethernet is very cost effective and it CAN at least in theory
get you better latency (over wire to cache on server) than local
rotational latency would have been.  You might add several controllers
and make kind of a star network.

Combine fast ethernet and NQNFS, for that matter.  Measure performance
incrementally as you turn on fast EN and then NQNFS (or vice versa).
You will need to do this step anyway even if you did your buffer hack
in order to show that you received any gain from the hack.