So i got to play Lee Sin a bit lately, and i quite liked it, so here is the build i often use:

Long Sword > Sheen > Boots of Swiftness > BF Sword > Phage > BF Sword > Last Whisper > Frozen Mallet > The Bloodthirster > The Black Cleaver > Banshee's Veil

This is pretty much it, won't explain why have i chosen these items, but they will get you some really nice AD burst

Hope you like it, and try the build out!