Using makepkg --holdver and definining the specific revision in _svnmod makes it quite easy to build a specific revision.
I tried my best with mercurial, but it always checked out the latest revision.
How can I get specific revision builds with mercurial and makepkg?
I think that with the new pacman 4.1 / makepkg, you can use a new syntax in the sources array to select a specific revision. See http://allanmcrae.com/2012/08/changes-t … n-makepkg/ .