Here's some interesting and possibly hopeful news from Wellesnet,
the invaluable web site resource for all things Orson Welles.  It
seems that Beatrice Welles, Orson Welles' daughter and one of his
heirs, made a legal claim against Turner Entertainment over the rights
to The Magnificent Ambersons and a couple of other films.  Court documents tracked down by Wellesnet reveal that the claims with regard to Ambersons have been settled.  This may explain why Ambersons
has not yet appeared on DVD in the U. S. and may be a sign that it will
be coming soon.  Let's hope.  This is one of the greatest
films not
yet available in the format in this country.  Others are:

The Big Parade
The Merry Widow
(silent version)
The Wedding March
City Girl
Falstaff (Chimes At Midnight)
Comanche Station