Costco has been selling Kirkland signature wines for a number of years and over the past year has filed label applications for some private-label spirits, including a single-malt scotch.
The focus on beer appears to be a new effort.
The beers are brewed by Gordon Biersch Brewing Company, a California craft brewer. Interestingly, Biersch also makes private label craft-style brews for Trader Joe’s.
They’re planning an amber ale, a hefeweizen, and a pale ale. The beers would appear under their "Kirkland" signature line, though I don’t know how wide a distribution they’d receive.
The "Brew" Blog also has links to the application document and label design (shown here).
As someone who has a both a Costco and (soon) a Trader Joe’s available in the same town, I’d be interested in comparing both stores’ versions of, say, hefeweizen in a side-by-side tasting… since they’re brewed by the same brewer, do you suppose they’d use the same recipe?