Possible, but the practicality of it being legally distributable is questionable. Apple's EULA for OSX does not allow OSX to be run in a virtual machine at this time. Only OSX 10.5 Server is allowed to be virtualized and it still must be run on Apple hardware. Additionally, OSX is not free software so you'd need to make sure that the person running the appliance has a license to run OSX.
So assuming it's an appliance of OSX 10.5 Server, you'd have to make sure that the host is a Apple box and you'd have to make sure there's a license or you're authorized by Apple to make some sort of trial verson of OSX.