Here is a quick overview of ballistic single stage to orbit designs dating all the way back to the sixties.
A current Japanese project, Kankoh Maru seems to be based in several ways on the Phoenix in particular. It's progressed to the point that cockpit designs are being though through apparently.
The Japanese are doing DC-X type research with their RVT (Reuseable Vehicle Test) rig. Unlike DC-X RVT is not likely to be cancelled. See RVT launch and land here