Unfortunately, as we all know, most Welles projects, especially public domain items, aren't attractive enough from a financial standpoint to get the bucks needed to get started.
As for the Arkadin remake, the producer appears to be a guy who produced big name films like Rain Man, Bugsy, and some others, but he hasn't done much of anything worthwhile the last 10 or so years, unless you're a fan of The Banger Sisters or Dragonfly. The screenwriter is/was Joshua Safran, who has written and directed one film, according to the IMDB, which looks like a small indie type thing. No director is attached that I could find. It is a dual American-European production.