The problem being, of course, that as yet there are no level 31 items. The Adventurer's Vault might remedy that, but for now I'd say just give them two level 30 items.
Or, since they're level 30 and should know the game, give them the equivalent value in GP and let them kit themselves out.
Just be sure to veto anything ridiculous, like 10,000 units of everlasting provisions, with the intent of pouring the food into a river or something.