Blizzard has just updated their FAQ regarding the Diablo 3 Gold and Real Money Auction House closure. The announcements answers questions regarding the fate of D3 items still up for bidding when the AH goes down.
What happens to auctions on the Diablo 3 gold Auction House
Players with items up for Diablo 3 trading on the Diablo 3 Gold Auction House need not worry about the closure. The auctions will expire normally and will be delivered to the winning bid, or returned to the seller. Users then have until June 24, 2014 to claim these items from their Completed tab.
Unclaimed items and Diablo 3 gold
For those who have Diablo 3 gold or items sitting in their Completed tab, they will have until June 24, 2014 to get them. After that, all items and gold related to the Auction House tabs on a Diablo 3 account will be permanently lost.