Here are the timing results of running my client and server nodes
through the onion system. The configuration is as follows:

  +--------+   +-----------+   +--------+   +--------+
  | Client |-->| Raw Proxy |-->| OR Net |-->| Server |
  +--------+   +-----------+   +--------+   +--------+

The Client communicated to the server via the Raw Proxy, using the
proxy interface to communicate the Server's endpoint address. The
Client transfered 48 Mb of in-core data to Server and timed the
transfer. The Client and Server nodes used 4 Kb buffer size for
the transfers. The Onion system was tested for the non RSA, fast RSA
and non-crypto configurations, using the non mixing versions.

For the non RSA configuration, the throughput measured: 54.60 KB/sec

For the fast RSA configuration, the throughput measured: 53.6171 KB/sec

For the non-crypto configuration, the throughput measured: 75.3677 KB/sec

The mixing version is expected to be even slower :(

From the previous benchmarks, the raw network speed for a Client/
Server configuration is around 30376.90 KB/sec. Dividing this number
by N=6 (the number of hops), the max speed we could expect to see is
about 5063 KB/sec, which is about 67 times greater than the non-crypto
throughput. I think the next order of business is to examine the
architecture of the current implementation and either analytically
and/or experimentally, try to determine the cause of the performance
degradation. Hopefully there is a "magic bullet" that might solve this
problem. At least the results suggest something is going on that is
not cryptographically or number of hops related.