Infamous Adventures did some VGA screenshots for this. Are they ever going to finish it and release it?

Probably not. They talked about it once or twice on the Space Quest Historian podcast (as well as on on his YouTube channel), and apparently it was never truly planned. They just had a few screens ready to show at the end of their SQ2 remake as if the game would just continue on to the next game, but they ended up scrapping the idea.