Here's the latest from the Wisconsin Supreme Court. In Waller v. American Transmission Co., LLC, No. 2013AP805 (July 16, 2013), the court held that when a partial taking for an easement for transmission lines substantially impaired the economic viability of the remnant parcel, the condemnor is liable for taking the entire parcel.
Gideon Kanner summarizes the opinion in "When Must the Condemnor Take the Whole Parcel, Even Though it Wants to Take Only a Part of It?" ("So we won’t go through the whole megillah in anything resembling detail. But the court’s bottom line is clear: the condemnor — in this case a public utility seeking to take an easement — must take the entire larger parcel and pay for it when the owner so wishes and in the after condition the property, if subjected only to a partial taking, would wind up in an uneconomic condition.").
Worth reading, especially for you Wisconsin practitioners.