Timothy Sandefur has an extensive post on "The Kelo Backlash So Far." His conclusion--it hasn't accomplished much so far. Few states have had an opportunity to consider the issue and those that have acted have done so with limited effectiveness. He has a detailed discussion of the provisions of several laws and is unimpressed.

He writes (in part):

In the months after the Kelo decision was announced there was much talk of a "backlash" in the states. Since state law can provide greater protections to people than federal law does, people hoped to change state law to protect themselves from eminent domain abuse. But, as I argue in a forthcoming paper (which will be posted on SSRN shortly), the backlash so far has accomplished little.

Most state legislatures have been out of session since shortly after Kelo was announced, which means that so far only four states have enacted laws in response to Kelo: Alabama, Texas, Ohio, and Delaware. Unfortunately, these four provide little protection for property owners, despite their big promises. In other states, the situation has been even more disappointing. California's legislature considered three measures to limit eminent domain abuse, and turned all three down, even though two of these would have been band-aid solutions that would have done very little. When the other state legislatures come back into session in January, can citizens of other states hope for greater protection? Only time will tell, but I'm pessimistic. There are two major obstacles to serious eminent domain reform: the public choice effect, and the sad state of American political philosophy. Still, there may be reason for optimism: the Pennsylvania state house has passed a bill which, if enacted, would create excellent protections for the state's property owners, and the U.S. House of Representatives has also passed an excellent bill limiting the availability of federal funding for projects in which eminent domain is used for economic development.