I have purchased a case...and I have modded it just enough that it is NOT going back to the Guitar Center. The cases that are *close* seem to come in two flavors... Either they are slightly too short, but otherwise fit almost perfectly. Or they too big in the body and to narrow for the headstock.
I never did find a case that fit overall as well as the Jack Casady case that fits the ESB-4 beautifully, big ears and all.
I finally reconciled myself to the fact that no one makes a case like the Jack Casady...just a tad longer. So I would need to mod a case. The one I decided to mod is a Road Runner RMMBA17 acoustic bass case. It had two issues. One is that the headstock area was a little too small for the E-string elephant ear. On the good side there was a good amount of space between the top of the headstock and the top of the case. In a well-fitting case, nothing touches the headstock with the case closed. The heastock would probably fit if I could remove some of the polystyrene-like foam next to the tuner. The solution turned out to be easier than that. When compressed, this foam stayed compressed. So, I clamped it overnight and got a good indentation around the E-tuning peg.
May not look like it in the pic, but the E-tuner does not touch the padding on the inside of the case.