>>434
I have no expert knowledge of Japanese language. So what I say is only a guess.

> this form isn't any different than the use of 〜て as a connective form (座って食べる) and いる, as in to exist.
I have never interpreted 〜ている like that, but come to think of it, yes, your intuition could be right.
When written in a kanji form, いる is 居る, meaning being present somewhere.
When we are eating, we are eating and at the same time we are present at a place where we are eating.

> can there be ambiguity in meaning between a resultant state and continuative action?
> For example, can "パンを食べている" mean both "(I) am eating bread" and "There is bread which has been eaten"?
Yes, I think there could be ambiguity as you say.
But normally, when we say "パンを食べている", it means "(I) am eating bread."
As for your second interpretation, "There is bread which has been eaten", we will say "パンを食べてしまっている" in that case.