This is the test I tried doing: I make a new patch (test.pd), inside I make a subpatch [pd blah], and inside blah, I put several [outlet]s:

Clearly, the outlets on the subpatch are so tight close to each other, that it makes sense that I would "stretch" the width of the [pd blah] object:

Great, it stretches, the outlets are now individually visible... So I save the test.pd, close it, reopen it again... and [pd blah] is again just as tight as on the first image?!

Does anyone know, if there is some sort of a trick, so I can save the "widened" [pd blah] object in my test.pd patch?!

I quite like a squiggly line made of "tilde"s.....
But I am open to suggestions.

There does seem to be a limit though, that I don't remember applying to abstractions......

Of course the longer but more sensible (and ....correct) way of doing it is to right-click the [pd blah] in the main patch and set its size in the canvas "properties" pop-up. There is I think no limit doing it that way.
David.

EDIT: if going through canvas properties, you must have "Graph on Parent" enabled, otherwise the size is not settable (and is ignored); but that is not really a problem, the default rendering is the same; also the default height for object boxes seems to be 18 pixels in PD vanilla...

Btw, the limit that you noticed - I'm pretty sure there is a similar kind of limit of text character width in a comment box, so I guess it makes sense it is also applied to object boxes (at least 'pd' subpatch ones).

Many thanks again!