Ditko drew the profile images for four of his creations for DC's first WHO'S WHO character directory series, including one of the characters published by Charlton and then-recently bought by DC, the Question.
Apparently there was some preliminary talk at the time of Ditko heading a revival of the character at DC, but not too surprisingly it didn't seem to go too far. It could have been interesting, certainly this page shows that he could still do some great artwork on the character. Well, at least we got this one great image that sums up some of the visual appeal of the character.
Vic Sage remains one of the definitive Ditko characters and an interesting middle-ground of his career, with a strong philosophical basis but with a stronger storytelling, characterization and dramatic sense than some of his independent work.