I got my Logitech Slimcombo case in 2 days from Apple. I came here really to update that my search for the keyboard cover for my 12.9 Pro has ended and saw this thread. It works exactly as I wanted--in fact I am typing on it in my lap. I fold under the front wrist protection in front of the keyboard as they suggest and it works great in my lap--and of course on a table or desk. It works good as a closed case too as you would expect. I have waited for a year and a half to find the right one but when I saw it, saw a video on Logitech's site, etc--ordered it from Apple right away and it was in stock and shipped free. It does have a loop for the Pencil and I'll probably use it some but I store the Pencil in a case with a place for the tips, the camera CC dongle, etc. All in all--the Logitech is almost perfect with backlit keys, protection for the back (you have to buy the silicone back for the Apple cover) and really easy connection--or unconnection. A definite recommendation.
Should say for clarity--watched WWDC, saw the new Ipads and wondered about accessories and went to Apple store when it opened--and saw the case in stock then-so ordered the next day after doing a bit more research--so you should expect it immediately.