“Forget about plunking down thousands of dollars and putting your name on a yearlong waiting list — to score New York’s latest “it” bag, you’re encouraged to eat the cow it comes from first. Sold exclusively at the Williamsburg restaurant Marlow & Sons, Breton tote bags boast supple leather and a price tag that ranges from $300 to $400. But buying one isn’t so easy. “We are keeping it really small, and for our customers at the restaurant who have eaten those animals,” Breton designer Kate Huling, 32, wrote in an e-mail about the small production of her new line.”