Quote Originally Posted by basicmonkey View Post
Following the install of Snow Leopard from a retail DVD, neither machine's ethernet port was available.
The reason the Ethernet did not work is because your Snow Leopard Install DVD was older than 10.6.3. The Mac Mini was created after the release of 10.6.3 which is why the ethernet port did not work correctly.

Quote Originally Posted by basicmonkey View Post
I was informed by Apple that the relevant driver to support the port was only available on the restore disk.
Apple support is notorious for not indicating the true nature of the issue back to a user. The issue you had was that until the 10.6.3 update, OS X did not have a driver for the new hardware, ie 2010 Mac Mini. (Also note the same is true for the 2010 Mac Pro. However it is covered from 10.6.2).

If your install DVD is 10.6 then the solution is to clean install. Then copy the 10.6.x update to a USB or Firewire Drive and installed it manually. This will update the drivers and fix the connectivity issues with the Firewire, Bluetooth, Ethernet, and IR port.

A big thing that changed with the Mac Mini hardware was the SATA controller. Prior to 10.6.3 the Mac Mini SATA driver was for multi channel and unfortunately the new 2010 Mac Minis are single channel SATA.

This doesn't matter to most unless you try to create a RAID Stripe across the two internal drives hoping for a performance increase.