Shares were once a big winner, but now they're well off their peak price. Carnival (CCL 0.67%) is firing on all cylinders right now. The business is seeing strong demand and posting record revenue. Shares have soared 45% in the past 12 months, rising faster than the broader S&P 500. But this cruise line stock still has a long way to go to generate a positive investment return for some of its longtime shareholders. These investors are likely still very much in the red. Along the same vein, what's the highest ...