This one is difficult to explain, but perhaps this video says it the best:
From my limited Rhino knowledge, it would be like having a “loft” with a built in bulge that basically works like a “blendsrf” inside the surface and adjusts itself with history as blends do…
…but I bet there’s a different name for it in Rhino if it exists. 
Hello - there is not such a tool in Rhino - It might be possible to hack something that would work in a script, in fact I might have done something in the past, I’ll look around and see if there is anything worthwhile.
-Pascal
Hi Pascal,
I remember the old post for this request way back in 2015 but the script isn’t downloadable anymore, were you ever able to find it?
I really hope it makes it into the loft tool permanently in the future. Pretty please with sugar on top. 
Hm. well, my script is such a hack it is really not terribly useful… I’ll see if I can make anything at all that is even slightly less hacky…
-Pascal
Anything new coming for Rhino regarding this feature?
It may be helpful to know what modeling problem you are trying to solve here? How is it used and what are you trying to accomplish?
can you show a use case that clarifies this request?
I think this is: Loft two curves and then interactively pooch the middle up into crowned surface,.
-Pascal
It’s all about speed and design iteration.
But you can replicate it with basic point editing. And if you’re trying to make Apple-style domed surfaces, please be aware those are built exclusively through hours of brute-force point-pushing.
Here’s a thing that might, or might not, make it a bit easier -
CrownLoft.py (3.9 KB)
Updated here to accept surface edges.
To use the Python script use RunPythonScript, or a macro:
_-RunPythonScript "Full path to py file inside double-quotes"
It selects the middle row of points, optionally adds a named selection and names the surface accordingly so you can keep track.
-Pascal
In surface modeling from an aesthetics point of view you try to avoid any straight surfaces, as i also model in alias, this feature is being used all the time and i miss it alot in rhino, many times out of lazyness i end up not crowning my surfaces and it just makes some parts look dull.
also, when youre working with alot of surfaces, you dont want to do it all manually, would be nice if its available as a preset.
I tried this script now, but not sure I get it.
My goal is to be able to move the curves around and simply not have to think about the surface, since that will always automatically have a nice curvature, regardless of what you’re doing to the curves…
Anyway, this is one of the earliest threads I made when I started out with Rhino I think, and since then I’ve discovered that all of these kinds of requests are kind of moot until history becomes more robust. Until then, there can be no fast design iteration in Rhino.