[jeffy]

You may have trouble getting perfectly clear extract beer, if you use steeping grain, due to unconverted starch that is present in grains that are steeped and not mashed.

I added a tablespoon of wheat flour (during the boil) to my last wit, and the stupid thing has dropped crystal clear after a couple days in the fridge. How does one go about getting starch haze? How much starch does it take?

My witbier turns crystal clear in the keg after a few weeks, too.  I have tried throwing flour into the keg and shaking it up, but it still drops bright.  I have been tempted to get this product:
http://www.wyeastlab.com/com_b_productdetail.cfm?ProductID=12

[majorvices]

Irs so funny the different experiences we brewers have. It's very rarely been the wheat or wit beer for me that turns clear. They always have sufficient haze. Maybe I drink them too fast.