I injected a GrailsApplication reference into my bean and created a closure that I passed to a new Groovy Timer instance. Inside the closure I'm able to invoke the dynamic finders on the domain classes because I can fetch a new instance this way:
def person_class = grailsApplication.getArtefact("Domain","Person")
def person_instance = person_class.newInstance()
That's simple enough, to actually call the finders (in this case "list") the next step was:
def results = person_class.metaClass.invokeStaticMethod(person_instance,'list',null)
Next plans are to create a generic way of exposing the ability to call the dynamic methods so that any Groovy class in the app has has access to them.