I've heard enough testimony that Perfect Pitch can be developed--but when it comes down to it, in almost any circumstance, having Perfect Pitch is not any more beneficial that good relative pitch.
Relative pitch is the real important skill/ability and can be trained fairly easily.
Perfect pitch is at best a parlor trick, and at worst an annoyance.
I have encountered some people with such attuned perfect pitch that they actually find listening to most music to be annoying. Apparently to them, the majority of music sounds out of tune (which it is in certain aspects)