WOAH.
The L who never shows his face, in Volume One of Death Note... that's not L. He's so very, very different. Examples(all in Volume One):
Page 92, top right panel - Is that decent posture I see? NOT L. L doesn't do the whole 'standing up straight' thing.
top left panel - Curly, light hair. L has straight, spiked, dark hair.
bottom right panel - Hair again.
Page 107, bottom panel - Hair.
Page 123, bottom left panel - Posture again. Also, his clothes actually fit, and you can see the difference in hair again.
In addition, the L portrayed in Volume One is more eccentric and excitable than the one we know and love.
So, who's this L im