FYI: here is a photo of the sign at the T7 taxi pickup, along with the number to call to get a ride. Shockingly, there was actually an agent there when I returned a few weeks ago to call the taxi for me. It was the Sunday after Thanksgiving, so a very busy day at LAX, but I was the only person in queue. The 25 mile taxi ride to DTLB was only around $72, which is only a little more than I pay for the ride to LAX (without the LAX fee).