Modern Warfare 3 was originally slated to get just 20 pieces of new downloadable content over the span of nine months. However, thanks to the way Elite has freed Raven Software, Infinity Ward and Sledgehammer Games from the typically constraints of creating DLC, the teams came back to Activision with far more than 24 ideas.
VP of Call of Duty Digital, Jamie Berger, stated that that number "could go higher," but nothing is 100% confirmed. Before you pissy anti-Call of Duty dudes get in an uproar, note that the extra four pieces of content is still part of initial Elite premium packaging. Plus, if next week's first packaged content drop is any indication, Activision is including more stuff than we're typically used to in their DLC packs.
As for the Call of Duty Elite service itself, there's a ton of new features being added in the very near future. Expect things such as clan leveling, new programs for Elite TV, mobile app updates, tablet support, Spec-Ops leaderboards, and more.