LEGO Ideas member Masman8675 has proposed a BTTF 1:1 Scale Hoverboard Model over at LEGO Ideas and it needs your votes to happen:
I have tried to create an extremely accurate LEGO version of the hoverboard used in the BTTF movies. It’s to the exact specifications of the prop used in the films: 71 centimeters/28 inches long, 20 centimeters/8 inches wide, and 3 centimeters/1 inch thick. In LEGO, that translates to: 90 studs long, 25 studs wide, and 3 bricks thick. It would be more accurate at 2 and 2/3, but that would look less accurate, and could possibly compromise the structural integrity.
This set would come with: The Hoverboard Model of course, and two minifigures: Doctor Emmet Brown in his 2015 attire, and Marty McFly in his 2015 clothes as well. The whole set is made up of 3,680 pieces: the full-sized Hoverboard model – 3,663 pieces, the minifigures with a stand and a minifigure scale hoverboard – 18 pieces.
Sounds good to me.