Sorted iterator for mappings

Often I want to iterate over a mapping, for some kind of display
purpose, and want to run through the elements in order. As far as I
know, there's no easy way to do that at the moment, so I usually end
up doing this:

foreach (sort(indices(some_map)), mixed key)

and then work with key and some_map[key]. In contrast, I can iterate
in arbitrary order thus:

foreach (some_map; mixed key; mixed value)

It'd be nice to have a way to use iterator syntax, but with a
guarantee that they're sorted. I've put this together as a
proof-of-concept:

https://github.com/Rosuav/shed/blob/master/sort_mapping.pike

Is there a better way to do this?

Could something like this possibly be added to the Mapping module?

ChrisA