Unfortunately I don't have an idea.
Logitech pulled similiar crap on me when I got an RMA for my speakers (replaced the Z-680 with the Z-5500 because they said they don't make the Z-680 anymore). Not only did they stop making the Z-680, they are on short supply of the Z-5500. I've been waiting since Feburary 8th.
It really depends. I'm thinking since these motherboards are in greater demand, they will get some out sooner. Maybe you'll see it sooner. Check out there website or call the store you ordered from.