[freebeard]

I padded the list with four-wheelers. Add Tucker.

Davis tricycle:

Despite raising $1.2 million through the sale of 350 dealerships, the Davis Motorcar Company failed to deliver cars to its prospective dealers or pay its employees promptly, and was ultimately sued by both groups. The company's assets were liquidated in order to pay back taxes, while Gary Davis himself was eventually convicted of fraud and grand theft and sentenced to two years at a "work farm" labor camp.

en.wikipedia.org/wiki/Davis_Divan

Dale reverse trike (70 MPG for $2K in 1974, the first gas shortfall)

The company had already encountered legal troubles when California's Corporations Department ordered it to stop offering stock for public sale because it had no permit.[1]

Rumors of fraud began to emerge, followed by investigations by a TV reporter and some newspapers.[2] The California Corporation Commission began an investigation as well.[10] Although Clifft said he still believed in the project and said that he was promised $3 million in royalties once the Dale went into production, he only received $1,001, plus a $2,000 check, which bounced.[2] Carmichael went into hiding, and was featured in a 1989 episode of Unsolved Mysteries,[11] which detailed the fraud behind the Dale for which she was a wanted fugitive.[12] She was eventually found working in Dale, Texas, under the alias Katherine Elizabeth Johnson,[9] at a flower shop. She was arrested, extradited to California,[2] tried and sent to prison for eighteen months.

en.wikipedia.org/wiki/Twentieth_Century_Motor_Car_Corporation