If you are EU based however, as of April 2015, you will need a current EASA licence to go with your FAA one flying an N-reg based in the EU. However the Channel Islands are non-EU! (Ideal if based there)
Same for the Switzerland. In our company we operate several M-registered aircraft,and most of the pilots fly with FAA Licenses. So far no one has been put into the process of getting an EASA license, but maybe its because the company is registered in Switzerland.
I'd be eager to see how the Swiss will solve this issue.
Last year EASA prolonged the new implementation for April,2015. Rumor has it they will just keep delaying this procedure.
I guess we all going to find out pretty soon.