I love Ikea, too. I bought several pieces in the past year, including my splurge at the end of year sale, where I bought 2 Alex cabinets on casters and two Kallax 2 x 2's. I already had 1 Alex and a 4 x 2 Kallax. I still need to put the second Alex together.
It turned out that the 2 room dividers I bought when I first moved into my house 6 years ago are the previous incarnation of the 4 x 4 Kallax units.