The upscale NYC-based Mexican restaurant chain Rosa Mexicano previously shared plans for an April opening via a Craigslist job posting, but now Grub Street has it that the company intends to open its first Boston location on May 1. Grub Street also notes that Rosa Mexicano has partnered with Top Chef Masters contestant Jonathan Waxman, who is also chef-owner of NYC's Barbuto, for consultation on the menu. What does he have in mind? Lamb neck enchiladas, not a world apart from the lamb neck tacos at The Painted Burro, which recently opened in Davis Sq. Rosa Mexicano comes on the heels of last year's upscale Mexican restaurant boom and will be joining Papagayo and Temazcal, which are both less than a mile away.