Technology has made a once-inconceivable idea a commercial reality ... almost.There's rarely a shortage of compelling stocks to buy. A millionaire-making prospect though? That's a different story.These investments require a revolutionary product or service, enormous demand-driven market growth, savvy leadership that can navigate uncharted waters others don't dare enter, and a little bit of lucky timing. Electric vehicle maker Tesla and e-commerce giant Amazon are two examples. Both have proven very rewardin ...