I tried a few of them on the alternate specular node, but didn't like what they were doing . I guess I could go back and spend a day just playing with the nodes and see what I can come up with. I don't have BB's knowledge of this (something tells me he's forgotten more than I will ever know), but it wouldn't hurt to experiment.

Try using your bump map attached to a spec node hooked into the alt spec channel, just for starters. That's only a small blasphemy against the Node Cult, I'd imagine :) , but it might give you some more control in long-distance renders while allowing you to still have the nice closeup without having to change any values between renders. Take a look at the Poser manual for a brief overview of the different sorts of specular nodes. (Note: It's terribly brief... not really stating many differences. But, there are some that are detailed.) Make sure any black&white bump map is set to a gamma correction of 1, btw. (It looks like you've already done that, but just making sure.)
A sort of "fish scale" effect, with/without the iridescence, is probably what you're looking for. Searching for a free shader like that might help you fine-tune yours.