A colleague of mine has been involved in some consultancy work for Toyota UK, and informs me that following a recent audit they have discovered a long lost prototype of a convertible Supra (not an Aerotop).
Developement work commenced using a specialist team here in the UK, but was abandonded around 2000. I understand this prototype, the only one remaining, had been languishing for a number of years in the garage of a Toyota development engineer.
From what I can gather, the hood folds down into where the back seats normally are, i.e. it is a 2 seater only.
He has got me this photo of it, and will try and find out more