Is there any information in the docs or online for the suggested spec requirements for Unity's master server?
There was a forum post on this a few days ago, I will just link to it : Topic
The outcome was, very low. The master server is pretty much just a list of games and sends them to connected peers.
It looks like the master server isn't quite ready for primetime:
Hopefully there will be some hardware suggestions for host servers when the master server software is updated (read fixed) in Unity version 3.