Well, technically there is a Hefeweiser...sort of. Anheuser-Busch owns Widmer, who of course are known for their Hefeweizen.
Personally, I like Pyramid Ale's Hefe, and their Apricot Weizen. Mmm. Tasty.
But those beers still don't equal a local craft brewer's Wit.
http://oregontrailbrewery.com/