The recent claim that California' (and many other states') recall law is unconstitutional has now advanced to the next logical stage - a lawsuit. Supporters are looking to adopt the "replace with the Lieutenant Governor" model (though in a state where you separately elect Lt. Gov's -- and has a long history of splitting the Gov/Lt. Gov position -- I could see this lead to its own problems). I haven't read the filing, though I'm wondering how they deal with the fact that the state has treated it as a bifurcated election -- the recall is a ballot measure. The replacement race is a separate election, albeit on the same day.
Here's Professor Ned Foley's take on why he suspects this will fail.