Specifying filesystem destination for uploaded files

Posted on the RoR users list several days ago, no responses, so asking
here.

Currently, mongrel stores files uploaded via HTTP forms in temp files in
the
system’s tmp dir. Logical, works well, etc.

However, I have a need to move those files to a network store after
they’re
uploaded, and often those files are quite large, so it can take a few
seconds each to move from /tmp to the network store (since the move is a
copy due to the different filesystem).

I’m wondering if I can have mongrel store the uploaded files right onto
a
temp dir set up on the network store, so that my move into a specific
location is actually a move and not a copy.

Thoughts?

Thanks,
Dan