Developers often don't announce they work on a particualr plane unless they have something serious to show already. So it may happen that two companies work on the same airplane without knowing about each other. Another story is when a payware developer announces something and then never finishes it, or postpones it 2 years or so. Like Aeroplane Heaven L-1049 Constellation, it was announced in November 2007, and still doesn't look like close to release date. So what you propose is virtually impossible.
Sorry for being offtopic on your post again but PMDG announced that they will do Dash-its_a_secret after BAe Jetstream. May be Dash-8.
Just for the record, yes, I am very interested in your Do328. You have stated that it won't be payware, so it has no place in a discussion about payware, but the same as we don't have a native Do328, we don't have a native Dash-8. I'd be interested in that as well, because my system hates complex ports.
Sorry for being offtopic on your post again but PMDG announced that they will do Dash-its_a_secret after BAe Jetstream. May be Dash-8.