Related blog post: Go and Polymer so Happy Together
This is an example application taken from the official Polymer tutorial, but modified to use Go to serve the json rather than a static json file. This can be used as a basis point for your projects where you want to use Go and Polymer.
This is ready to use standalone or on Google App Engine.
http://go-polymer.appspot.com/
go get github.com/treeder/go-polymer
cd $GOPATH/src/github.com/treeder/go-polymer
go build && ./go-polymer
Then check http://localhost:8080
Since this is ready to use on App Engine, you'll want to use the goapp tool.
goapp serve
Change the application name in app.yaml to your application name (from Google Developer Console), then:
goapp deploy