Shay Levi played off my mac address retreival code yesterday and shared his own PowerShell script to retrieve a mac address. Here's another PowerShell script to retrieve a mac address using get-snmp from NetCmdlets:
By the way, the get-hex function in the above script was adapted from
The Scripting Games' ABCs and 123s, which doesn't actually appear to work - but did teach me about the -f formatter.