SOME UPTIGHT Americans are going loco over the peso. In fact, it's a real food fight. Pizza Patron, a Dallas-based pizza chain, is accepting pesos at its 59 stores in Texas, Colorado, Arizona, California and Nevada. The gimmick is aimed at the company's clientele, which is 60 percent Latino. The company has received thousands of angry e-mails and even death threats. The thinking was that folks might find themselves with a loose peso or two after trips to Mexico. So why not trade pesos for pizza? That sounds like capitalism. Everyone wants Latinos' dinero. According to marketing experts, Fortune 500...