If you are using the class books, there are two feats out of Song & Silence to consider. Expert Tactician & Quicker than the Eye.
Expert Tactician
Prereq: Dex 13+, bab +2, Combat Reflexes
Benefit: You can make one extra melee attack (or do anything that can be done as a melee touch attack, including attempts to disarm, trip, or make a grab to start a grapple) against one foe who is within melee reach and denied a Dex bonus against your melee attacks for any reason. You take your extra attack when it's your turn, either before or after your regular action. If several foes are denied Dex bonus against your attacks, you can use thisfeat against only one of them.
Quicker than the Eye
Prereq: Dex 19+
Benefit: While under direct observation, you can make a Bluff check as a move-equivalent actoin, opposed by the Spot checks of any observers. If you succeed, your misdirection makes them look elsewhere while you take a partial (stadard or move-equivalent) action, opposed by the Spot checks of any observers. If you succeed, your misdirection makes them look elsewhere while you take a partial action (standard or move-equivalent). If your partial action is an attack against someone who failed the opposed check, that opponent is denied a Dex bonus to AC.
Round begins:
Standard action - Feign, you win the check, the target now loses his Dex bonus vs. you allowing you to make an immediate attack via Expert Tactician.
Move-equivalent action - Quicker than the eye, you win the check, attack target who is again denied his Dex bonus vs. you.
Note: Expert Tactician only gives you ONE extra attack per round, which is why the Quicker than the Eye move does not grant you two attacks.
And there you go, two sneak attacks in one round. Mind you, this is assuming you win the opposed checks, which for the feigning was made much more difficult under 3.5 (was definiately needed).