AMC's other two big franchises, Breaking Bad and Walking Dead, have had recently announced TV movies.
BB will apparentally deal with Jessie after his escape, and maybe his attempts to rebuild his life, although he's probably going to have some trouble with the law.
TWD will have Andrew Lincoin return as Rick, and reveal perhaps where he's been for the past six years after Anne/Jadis got him on a helicopter for parts unknown.
Could a Mad Men follow up be a possibility as well? I haven't finished the series myself yet but I'm sure there's some things they leave a bit open-ended. Then again MM to me seems more like an ensemble whereas a lot of TWD was pretty much focused on Rick (and now pretty much Darly and Michonne). Ditto with Breaking Bad, mainly Walt and Jessie's story (Well, and Jimmy/Saul's/Gene's in the spinoff). Although Don was pretty much the "star" Peggy, Pete, Roger etc. got more or less equal time.