A brewer in Pittsburg has claimed to have made the first commercial American Kvass:

For Growlers this week: Big Hop Harvest (will this be the last week?), Black Strap Stout, East End Witte, and for the FIRST TIME ANYPLACE: Session Ale #5, Kvass – the first commercial Russian Bread Beer brewed in the United States!

I love Kvass and wish it were more available outside Europe.