Benchmarks For Linux And Solaris On SPARC Hardware?

NetJunkie asks: "We currently run several Web servers on Sun Ultra 5 workstations. We're interested in moving to Linux since there are some things we want to do which are expensive to do with Solaris. Are there any good benchmarks of Linux on Sparc against Solaris? We're rolling out PC hardware now, but we'd like to keep using our existing Sun boxes and good benchmarks will make this a much easier sell."