There are actually two kinds of attack damage shaco. The first is Burst Damage Shaco who abuses Deceive, Crit Damage, and pure attack damage (Infinity Edge, Sword of the Occult, Bloodthirsters) to deal obscene amounts of damage with a single strike. For this Shaco, you use 100% crit damage runes.
The other kind of Attack Shaco is DPS Shaco. This Shaco aims at abusing the Hallucination Fako to its full potential through use of on-hit effects (Malady, Black Cleaver, Madred's Bloodrazor) which are applied fully by both Shaco and his clone and Auras (Stark's Fervor, Aegis of the Legion), which the clone also emits and thus doubles up the effect. This kind of Shaco probably goes for a more balanced Rune Page, with attack speed or armor penetration in marks, HP in Quints, Dodge in Seals, and Cooldown in Glyphs.