I've got a beautiful whirlpool tub, but now need to add a shower set up. Will use exposed pipes once we figure this out.

So the question is -

Can I add a diverter to the existing set up (under the faucet perhaps or in line is possible) and plumb from that to a shower?
I really don't want to replace the existing fixtures.

Other option is to be a little funky and add an exposed shower on the other end of the tub (have a good 18" of oak decking and supply line access there. Is it possible to create an exposed shower set up? I really am on a tight budget and don't want to spend any more than I have to.