Again in the vein of simple to implement...you could set up several ghost machines that don't really exist but look as if they where connected to the IP machine through uucp. I'm not really sure what the From: address would look like, but it should be easy to generate.
If this was workable, you could create x ghost machines and randomly pick a From: for each message. True, the Inet box would be ID'ed, but as a transmission agent, not an originator.
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