Even though a sequel to Zombieland is a ways off - especially with the writers and directors suddenly finding themselves ridiculously in demand following the success of the undead comedy - Sony is already spitballing ideas and coming up with names for people they want to cameo in Zombieland 2.
The first film featured one major cameo (Spoiler Alert: it's Bill Murray as a zombie), and it appears they want to try and recapture that magic for the sequel. Bloody Disgusting reports that they are already 'searching for someone iconic along the lines of "Harrison Ford" or "Anthony Hopkins"'. The issue is, of course, that there's no point writing a role for someone, if they're supposed to be playing themselves, if they don't want any part of it, so the studio needs to get an actor to agree before it becomes part of the script.
Of course, wanting Ford or Hopkins is very different to them saying 'yes' to appearing, but I wouldn't count either of them out. It could be a great move for Ford, whose box office power had swayed, and could do with making himself seem less serious.
Bloody Disgusting also say that currently Jesse Eisenberg is the only person officially signed for the sequel, although it's presumed that Woody Harrelson will also be back, with his character, Tallahassee, 'going head-to-head with a hunky rival.' Whether they'll be able to get Emma Stone back is another question, as her career is currently going into the stratosphere with the likes of The Help and Spider-man.
As yet it's uncertain when the movie might go into production.