My money is on polyphonic analog pitch shifting. You know, bending notes up and down.I'm betting Rubberneck is true pitch vibrato - as in a rubbery neck that goes out of tune from hand pressure. That is an effect that can be implemented by a LFO variable analog delay.
That's just it. The GSP1101 is a phenomenal processor with the MBB firmware. Also, it's been roughly 10 years since it came out so, one would think it's just about due for an update.Honestly, why did you guys abandon multi effects? An update to the GSP or the RP1000, if you will.