I am seeking some advice on hardware for a dedicated SSH box. I can't
seem to find any performance statistics for anything but SCP/SFTP
transfers and the HPN patches for fat pipes.

The goal is to support 500-1000 simultaneous SSH sessions, which are in
TCP port forwarding mode only. The data travelling through the tunnel
will be small (about 1KB over the course of one minute).

The first question is whether crypto accelerator cards are actually
useful with this type of scenario (on the server)? I looked at the
OpenSSH code and it seems that it only uses crypto accelerator cards for
specific tasks (keys on a smartcard). The only calls that I see to the
OpenSSL functions that provide hardware acceleration (ENGINE_set_*) are
in "scard.c" and "scard-opensc.c" files. So OpenSSH effectively doesn't
use any hardware accelerators supported by OpenSSL? Is this correct?

The second question is how much RAM/CPU would be necessary to support
500-1000 simultaneous connections (assuming no hardware accelerator
support)? This will probably be AMD64 CPUs. Anybody have some
statistics or guidance they can share?