This is sweet. Concise but still expressive:
// both work, 2nd is new in Grails 1.1
//def itemList = Item.findAll("from Item item where item.id in (:allIds)", ["allIds": allIds])
def itemList = Item.findAllByIdInList(allIds)
Check out the new features in Grails 1.1Beta2
If you need an IDE for this beta release, you can try the Intellij IDEA EAP release for 8.1, the IDEA 8.0.1 release does NOT support Grails 1.1Beta2.