Apologies for incorrect statements, but reading your informed answers it all seems to come down to the wings.

If we could manage the abort options without wings then the crewed vehicle could sit on top of the stack.

What would this require?

My thoughts:

1) A recovery ship, or ships, on permanent duty in the Atlantic on launch days. These could be equipped as hydrographic research vessels and do useful scientific work the other 90% of the time. Or be military vessels with force-projection capability to keep troublesome nations under control.

2) Depending on how tight the options are, a ship or ships in the Pacific and Indian oceans, same rationale. (hopefully there should be more control on descent location from orbit/suborbit, hence wider spacing) - but one would need to cover the full lattitude band traversed by the craft!

3) Arrangements for emergency onshore landings across the entire ground track of the craft- which leads to major political problems. At present, with Russia and China playing "good guy" it's easier, but one still needs to avoid an accidental arrival in downtown Baghdad, for instance.

Additional or alternate options would have large recovery aircraft available to deploy to the splashdown/touchdown site. These would need to include helicopters and in-flight refuelling.

It starts to look expensive and complicated and a military-based solution will lead to political difficulties.

(I'm thinking as I type, hence the rambling structure)

Hmmm....

Not so easy. Guess I'll go and read some background stuff about the original design of the Shuttle. A lot of this stuff must have been discussed back then...