The dvd disc available from German amazon features both the silent & sound versions, though this is not signalled in the product description (enlarge the cover image to confirm...)
 
 
frank krutnik> Date: Sun, 26 Oct 2008 10:53:51 -0400> From: [log in to unmask]> Subject: [SCREEN-L] searching for silent blackmail> To: [log in to unmask]> > with apologies for duplication . . .> > > > does anyone know whether there are copies of the silent version of> hitchcock's BLACKMAIL available on DVD or VHS?> > > > all the copies i've been able to trace are [or seem to be] the revised> version with sound that hitchcock made after sound became available to> him during the filming> > > > any leads very much appreciated> > > > mike > > > ----> To sign off Screen-L, e-mail [log in to unmask] and put SIGNOFF Screen-L> in the message. Problems? Contact [log in to unmask]> 
_________________________________________________________________
X Factor: latest video, features and more. Click here!
http://clk.atdmt.com/GBL/go/115454063/direct/01/
----
Screen-L is sponsored by the Telecommunication & Film Dept., the
University of Alabama: http://www.tcf.ua.edu