Hey, first thanks for reading my post, I'm glad you were able to get some information out of it.
As far as I know, there is no real progress being made on it. Besides those OK, not that they're bad, they do their job, mods, they work, but, like you said, they can be better.
I personally don't know C#, or Unity, or anything, so I don't think I can be of any help working on a mod for DSL.
But I definitely think it is a great idea, and something I hope in the future is worked on, and done.
And as far as Sebastian working on DSL, I'm not sure if he's "forgotten" it, but I know he has interests in other aspects of Programming, specifically Graphics, from his most recent videos. You never know, he has gone on hiatus before with DSL, maybe he'll come back to the project in a little while or so.
But if your up for trying to tackle this project, no pressure, or anything, I definitely think it's possible, and that it would be awesome.