ShopKeep.com, a cloud-based POS developer that offers Windows and Mac based cash-register hardware and software, is launching a beta of a iPad-based POS system to compete directly with existing bulkier, more expensive touch-screen systems aimed at small retail businesses (such as bakeries, coffee shops or other outlets where there are fewer than 150 items for sale). The pilot program will debut at popular Grand Central Station coffee shop Joe in New York City on January 18th.