Circuit Maker just released a brand new cloud based circuit designer with no limitations in PCB size or amount of layers you can work with.
The only drawback is that you need to be connected to the net in order to run it and work on your designs. Without the live connection you can't work on anything.
You are also limited to two sandboxed projects that are off the community grid everything else becomes open to the rest of the Circuit Maker community so anyone can fork/edit/collaborate on your design. More info here http://www.circuitmaker.com/