NAT proxy concepts

[vizion communication]

Hi Guys

I have been taking a close look at some networking
opportunities which are being frustrated by the limits which
are imposed by NAT. In particular the constraints impose by
the embargo on double NATing have an impact for a project I
am working on. Has anyone ever seen anything which I would
conceptually describe as a reverse NAT proxy?

What I want to be able to do is to be able to create a
heirarchical  tier of networks each one of which
communicates to the network above by using a modification of
NAT  enjoying the capability of identifying a subnet number
and client.

Does ayone know enough about this subject to point me in the
right
direction (which may be - forget about it there is no way it
can be done..:-)

David