Marc Laidlaw (story writer) wrote a letter "Epistle 3" - its said here, you can search on google. Especially when people now know the story about what HL3 would look like, many are rushing to Unreal Engine and other engines to make HL3. Will they be really succesful?
I mean it was known years ago that freeman has to go to Borealis and etc. And if someone is making a mod thats on Source, will it be played?