I googled ["Web services" performance] and got a bunch of nice hits
CA's product is interesting, lets you track the actual performance of public web services. CA seem to be using WSDM to do this.
I'm more interested in characterizing the attributes of web service performance that would lead to capacity planning methods for web services infrastructure.
As I find more about what is the actual state of the art, I'll list links to it here, then start synthesizing and extending off into uncharted territory.
I think I'm down to do a Grid/Web Services tutorial at the CMG04 meeting in Vegas in December so this is a place for me to collect and discuss some of the content in blog form.