Just checked on the .56 cabinet and was repromised another month out. So now is late May.
Would be pleased to give Erich some business but he needs to show he can be relied upon to deliver as well. @carbidetooth and others are great for single units but also is an understandably more expensive approach.
That's really frustrating. As a temporary solution could you use the larger 1.16ft3 tower and make two bookshelves? Obviously not ideal, but a relatively simple cut in the middle, and now the only thing you're missing is the bottom of the speaker? Cut in two, the price seems in line with what the .56 cabinets were...I think.