With a firmware password set on a Retina MacBook Pro, what are recovery options?
It is possible for the lost firmware password to be reset, but not by a normal user.  As an Apple Certified Macintosh Technician working for a third-party service centre, if someone brings in a machine that has RAM soldered to the Logic Board and they have forgotten their firmware password, I can upload the serial number and request a firmware password reset.  We're then provided with a disk image that can reset the firmware on the machine with that specific serial number.  I believe, but can't confirm at this stage, that the utility on the disk image may expire after a certain length of time.

For all those concerned about privacy, any technician that requests a firmware password reset will have their details logged on Apple's end — so if it's reset for nefarious purposes, the details about which technician performed the reset can be tracked down quickly.  The reset also requires direct, physical access to the machine - the password cannot be reset remotely.