If you have $10 billion to spare (and, really, who doesn’t?) you may be able to purchase the Dallas Cowboys—but not on owner Jerry Jones’ watch. The 79-year-old Jones, who bought the team in 1989 for $150 million, said in an interview he thinks that if he put the team up for sale the Cowboys could fetch “more than $10 billion.” However, we’ll never know. “Let me make this very clear,” he said to NBC’s Peter King. “I’ll say it definitively. I will never do it. I will never sell the Cowboys. Ever.” It seems like wishful thinking from the oil tycoon, as Forbes estimates the team’s value at $6.5 b…