The rumored 18W quad-core processors have apparently been cancelled. Similar to the 15", they were part of the H-series and did not have Iris graphics. However, a 15W (U-series) quad-cores are also expected be released with Kaby Lake/Coffee Lake processors next year. Apple have begun shipping 15W processors in MacBook Pros, so perhaps these could replace the 28W CPUs in the higher end 13" models. It would certainly make it more suitable for professionals while also having possible battery life benefits.