WoW Insider reader Aaron provided a very good macro for those of you wanting to make use of your focus target to maintain Polymorph on a focus target.
Here's the macro, ready to be copied and pasted into your macro interface:
/focus [target=focus,noexists]; [target=focus,dead]
/cast [target=focus,exists,harm] Polymorph; Polymorph
Come on back after the break for an explanation of what this macro does.