On July 30, the Libertarian Party filed a lawsuit in U.S. District Court against the District of Columbia ban on letting out-of-district circulators work in Washington, D.C. The case is Libertarian Party v Nichols, 12-1248. Here is the complaint.
Only six states still ban out-of-state circulators for all minor party and independent candidate petitions: California, Connecticut, New Jersey, New York, Pennsylvania, and Virginia. South Dakota bans out-of-state circulators for independent candidate petitions but not petitions to qualify a new party. Lawsuits against residency requirements for circulators are pending in California and Virginia.