The JSOP proposal [1,2,3] has a really nice patch notion for issuing multiple changes at once. We should consider adopting this mechanism.
[1] http://lists.w3.org/Archives/Public/w3c-dist-auth/2010JulSep/0008.html
[2] http://dev.day.com/content/ddc/blog/2010/08/introducing_jsop.html
[3] http://www.slideshare.net/uncled/jsop