CISCO IOS 12.x Virtual Switch

Hello list!. I want to virtualize a CISCO Switch with CISCO IOS 12.x to perform some test on its RA-Guard implementation. By searching over Internet I've found that its possible to virtualize some devices such as routers using GSN3 and a CISCO IOS image. Is it possible to do something like this but for a switch instead of a router?. Or does anyone have any suggestions in order to test CISCO's RA-Guard (or another implementation)?? Best regards. -- Daniel Espejel Perez