Look at this thread https://www.alternatehistory.com/forum/threads/wi-nasa-gets-the-flax-shuttle.325209/
You need a POD before January 5, 1972, the day Nixon approved the full size orbiter. There are all kind of shuttle concepts discussed there http://history.nasa.gov/SP-4221/ch8.htm
Yes! Reading the Flax Shuttle thread was one of the things that got me curious about alternate shuttles.
The table just above this link gives the expected development and launch costs of a Flax-style shuttle - development costs were only expected to be $800 million less (a saving of only 1/7th of the total development budget predicted for the full size TAOS shuttle). Costs/pound to LEO were expected to be double for the OMB shuttle. I wonder if both of those costs would have ballooned as much as the real shuttle's costs did? If they did, the OMB shuttle could turn out to be quite the turkey.
On the other side of the coin, if the costs turned out to be mostly accurate, the OMB shuttle could turn out to be an able and economical vehicle. NASA expected the smaller shuttle to be able to do 80% of the missions the full sized shuttle was expected to do - given the way the full size shuttle turned out to be more limited than expected, I expect the real comparison in capability would be that the OMB shuttle would turn out to be able to do 90-95% of what the OTL shuttle could actually do.
fasquardon