The author of the epinions review also is now a member of Wellesnet; I believe he posts more frequently under a different name however.
A lot of Arkadin issues were discussed earlier this year in this thread:
Being a public domain film, many different versions exist. From what I've read here, it seems unlikely we'll see a SE DVD anytime soon. While it is debatable, it seems that the version that may be closest to Welles' vision is currently owned by Corinth films. They don't release it on dvd, only on special order VHS. (Somebody here may trade you for it if you post in the Trading Area forum.)
I haven't had chance to read the article yet but recently emailed the author Jonathan Rosebaum and asked if the Corinth version, or any version could be called closest to Welles' final cut. He said no and that everything on the subject could be found in his article.