Beautiful: It is a great story. A contest of wits. A battle between equals.
Lies: There is nothing to suspect Light as Kira. Light could easily write 4 years worth of names and forget about being Kira. He could devote himself to University. L isn''t working via clues, he just wants Light to be Kira.
Light could have easily said "F you dude, I don't believe you're L". or simply gone to his father and told him "A freak at the University says he's L but the creep could actually be Kira looking for information on the police officers." See? Easy. Anyone could be a suspect, because there is no physical proof of anything.
Light has got to stop thinking of himself AS Kira. That's all it takes. If people are being Judged on automatic, (shrug) than there is nothing to link him to the murders.
In fact, there IS nothing linking him to most of the murders. There is no reasoning, in any way or form except supposition, to link Light to Kira. I suppose Kira could be George Bush! Well darn how did I come to that conclusion? Well I just decided that it was true. See? I can do it to. Anyone can.
Still, for the fairytale this is, its an enjoyable story.