I'm wondering if it could be Sunstreaker? Closest thing to a "concept" car in the '84/85 line up I can think of and I'd expect there'd have been reluctance by Lamborghini to authorise anything based on a customisation of an iconic design - possibly an expectation they had from conversation while negotiating the original mould?

Personally, I'd actually prefer a Jazz or Bumblebee but I don't really care who it is... I'm pretty certain I'll be getting it regardless!