Berkshire Hathaway CEO Warren Buffett is one of the world’s richest men, but that doesn’t mean he has champagne tastes. The billionaire investor was in Boston this week for a meeting with execs at Yale Electric. Afterward, we’re told, Buffett, his burly bodyguard, and a few folks from the Dorchester-based home appliance store headed over to Boston Speed Dog, the food truck in Roxbury that sells the most scrumptious hot dogs. Not surprisingly, Buffett loved the dog and joked that he wanted to buy the truck. When we asked Speed Dog co-owner Greg Gale about his brush with fame, he was confused. “Really? He was here? I didn’t even know,’’ Gale said. “I love his music.’’ No, we explained, it was Warren Buffett, not Jimmy Buffett. He’s older with gray hair and glasses, we said. “Now that you mention it, I did talk to him,’’ replied Gale. “He said he wanted to buy the place, and I told him, ‘You don’t have enough money.’ ’’