A finger building on Hunter Street in Long Island City—which is positively teeming with new residential development—launched condo sales a month ago… and already, 30 percent of the units are in contract. With a very Manhattan-y name, The Madison hit the market in late June, offering apartments starting from $500,000. According to StreetEasy, four out of six apartments that have been listed thus far are taken, with the two remaining priced at $575K and $560K, respectively. There are 14 apartments total in the modern, balconied nine-story building, which is tucked in a low-rise area south of the Queensboro Bridge ramp, west of where it turns…