Dear Mikep,
I agree with you that the idea of not allowing new "ethnic" restaurants inside the walls of Lucca, as it was reported by the news at the time, was offensive. However it seems that it was more the result of a local politician looking for some publicity, rather than a real "ban" on kebabs or similar restaurants. After January 2009 we didn't really hear or read anything more about it, even if it would be hard for me to say if new restaurants have actually opened since then.
The news was probably distorted a little in the news, as I have to say that Lucca and all of Tuscany are very open to different cultures, including from its gastronomical side.
I would definitely go on and include Lucca in your trip, it is a beautiful city worth visiting, and since it's quite small and close to Pisa, it can be easy to visit both in 2-3 days.
have a great trip, and if you have the chance, come back and tell us about it!
