Monocoque Li.
In 1962, Innocenti proposed a revolutionary design for the Series 3 Lambretta Li, the prototype featured slimer floor boards, in turn a new exhaust and kickstart were designed around this design. Tthe wheel rims and hubs only had 3 point fixings. The overall size and shape was the same as the production version of the Series 3 Lambretta Li other than the floor boards, however it never got to the production stages.
Image Copyright to Vittorio Tessera, Casa Lambretta, Museo Scooter e Lambretta Milano.