This weekend, thousands of Americans will cobble together Wall Street-themed costumes in preparation for Halloween. (Pre-emptive note: dressing in a suit and tie and labeling yourself “The One Percent” is not as clever as you think.) DealBook is here to help. Herewith: our seven best finance-themed costume ideas, with tips on how to pull them off at your parties this weekend. Zombie MF Global: Dress in tattered rags, tape “FOR SALE” signs to all your appendages, and wear a necklace that says “Credit Lines.” Tap it repeatedly. Have two friends dressed as ratings agencies follow you around, telling everyone at the ... (full story)