I also highly recommend the Heipi, Neewer LT32 (this is what I got and sold my aluminum Peak Design for), Falcam Treerot (friend has this one, it's quite nice), and Gitzo Traveler (I have the 1545). None of these get quite as small as the PD when collapsed, but it's only a matter of 1-2 inches for most of them.
BTW if you get one without a head, I cannot recommend the Arca Swiss p0 enough. Best ballhead I've ever used, I will never sell mine.