Tom, I've seen references to this in the current discussions about labeling wine with possible allergens. The FDA adopted the Food Allergen Labeling and Consumer Protection Act in 2004. It requires labels on every food or drink that contains one of eight major food allergens: milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat and soybeans.
The Santa Clara Press Democrat had an article about the subject recently. The article indicated that some barrel makers use wheat paste to seal barrels.
There's a news group in New Jersey who is investigating this question; there seems to be an issue for people with wheat allergens and for consumers of Kosher wines. The group has sent a survey around to a number of wineries to see what they know about the issue. So far, one response indicated that some barrel makers use the wheat paste instead of lime to seal barrels.
A bit of noise with little real info as far as I've seen. The information on fining with egg whites seems much more precise; I've seen warnings on New Zealand wine labels indicating that there may be egg white residue in the wine.
Regards, Bob