How best to handle multiple-authorship commits in GIT?

Hi,

I've been assigned a stack of patches to maintain and try and get upstream by my employer. Most of the patches currently have the authorship set to Val, but since I'll be maintaining them if they go in upstream and I've changed them a lot, I feel I should reassign the author field to myself so people pester me rather than Val with questions about them. However, I don't want to deny Val or any other contributor credit for their work on the patches.

I can see a number of ways of doing this, and am wondering which will be best:

 (1) Ascribe multiple authorship directly in the commit.  I suspect this would
     require a change to GIT and its associated tools.  That way I could put my
     name in the priority pestering spot, but doing a search on authorship
     would still credit Val and others.

 (2) Add an extra tag 'Originally-authored-by' (or maybe 'Coauthored-by' as I
     saw someone recommend) in amongst the 'Signed-off-by' list.  But that
     doesn't give them credit in a gitweb search without changing gitweb.

 (3) Don't actually modify Val's commits to bring them up to date, but rather
     create a historical GIT tree with Val's commits committed as-are and then
     add my changes to the top in a number of large merge commits (there have
     been multiple major breakages due to different merge windows).

     I dislike this approach because it doesn't produce a nice set of patches I
     can give to someone to review (which is a must).  Plus, for the most part,
     it's actually easier to port Val's patches individually.

Can GIT be modified to do (1)? Gitweb's display need only show one of the authors in the single-row-per-patch list mode, but should find a patch by any of the authors in an author search and should display all the authors in the commit display.

David