It was very interesting to listen to Jack Norris on the recent Wonders of Thedas podcast (I get it a week early as a Patreon supporter). He said that Green Ronin had been very interested in designing a pen-and-paper RPG based on the Mass Effect universe and indeed had made a pitch to Bioware to do so, but that the contacts involved had not been as keen as their Dragon Age counterparts.
It was probably years ago that such an approach was made, so I wonder if it might be worth revisiting the idea with Bioware, now that Mark Darrah (probably involved in Dragon Age in 2010) is higher-up the company ladder. With the 11 year anniversary of N7 day coming up next month, Bioware have Mass Effect on the back-burner but I suspect they would like to raise the profile of it. They are also probably finished with the Milky Way, so might be more happy for 3rd parties to influence 'canon' there.
I'd love to play a Green Ronin produced Mass Effect RPG!