Don't need a Bridge.
Sonos Bridge required? Really? I don't have one as I have ethernet run to a ZP100 or ZP80. Almost all of the products have at least one ethernet port and thereby remove the need for a bridge. The baby units (Play:1 and the like) may not have them though, but supposedly only one node needs the connection.
Then again the mesh network performs so badly at my place that I've ended up with ethernet to 4 of my 5 zones and a switch that supports spanning tree. Perhaps the updated mesh in the ZP90 and ZP120 would perform better, but upgrading costs too much for limited gain.