According to Fudzilla, the triple cored A6-3500 will be identical to the A6-3600 but with 1 core disabled. This means that it will have the Radeon HD 6530D with 320 stream processors and a core speed of 433MHz. The CPU core speed will be 2.1GHz with a turbo upto 2.4GHz and a TDP of 65w. Interestingly this may keep the 'unlocking' culture alive for a little while longer, though may require 3rd party intervention.
There is no time set for release.