A note for those who would like to use merging already: I'm maintaining an unofficial branch of Dpkg that is otherwise identical to the main one except that it's has (update version of the) patch of bug #120152 applied:
http://elonen.iki.fi/code/unofficial-debs/dpkg-merge/ Install package 'Imediff2' or do 'export MERGE2=/usr/bin/sdiff' to enable the functionality. - Jarno
