To be fair, even NASA hasn't, though political and engineering pragmatism forced the Agency to set aside funding for X-33 and other similar grand designs in favor of expendable boosters, leaving scram-jet's basic engineering to work with experimental remote-controlled aircraft in 2001.
They've enjoyed successes and mixed results in the Australian outback, for example.
As seen above, the thousands of people who've downloaded Martin Schweiger's open-sourced and free Orbiter Simulator program are well-aware of the possibilities of an intimate relationship between scram-jets in future SSTO hybrids.
But are such concepts practical?
In what may be one of the best summaries of the true state of the art, The Space Review published an article by Mike Sneed today that examines this "Holy Grail" of low-cost access to orbit and examines the scram-jet hybrid concept.
Read : "Assessing the practicality of scram jet-powered, single-stage aerospaceplanes," HERE.