CAN Capital is the big dog among a group of small business lenders that make high-cost, short-term loans to merchants who can't get the financing they need from traditional banks. This week, CAN is marketing a $191 million bond offering backed by interest payments from thousands of small business owners. As part of the process, CAN is giving the public a more detailed look into how the company markets its high-cost loans to customers, and how much it charges. The transparency is rare. Mortgage and credit card lenders often package risky loans and sell them to investors, but only recently have investors shown appetite for bonds backed by payments from unsecured loans to pizzerias, Irish pubs, and auto repair shops.