I don't think he has, unfortunetly. And certainly not with stupid Misa, no offense!! Simply because he doesn't really get out much. And, if he did, I'm positive that several girls would fall in love with HIM first!!!
I dont think so. I mean I fell in lvoe with him :P but no one from the manga he has fallen in love with. Its it simply because L doesent get out often because he hides his identity.