If you REALLY wanted to twink 5 box.... go melee. Then spend the gold to trick them out with gear. But melee does not lend itself well to 5 boxing for a whole host of reasons - among them positioning problems.

5 Melee shamans perhaps? Seems like a waste of time really unless you REALLY want to PvP @ level 19. Most classes are a waste of time to box at 19 due to the amazingly huge impact gear and expensive enchants has on your ability to stay alive more than 1 hit. Or, well, 5 hits