I can add 3 notables (Others can add more):
Famous Canadian Hockey player turned entrepeneur .... Tim Horton (Yes, the same Tim Horton from the ubiquitous Canadian coffee chain). Unfortunately he perished in his DeTomaso when he lost control on a highway.
World Famous and one of the all time great F1 World Champion and Team owner ... Sir Jackie Stewart.
Clay Ragazzoni raced a Group 4 as part of a DeTomaso campaign.