Today I opened up my RSS feeds to discover that the Apple co-founder Steve Wozniak closed shop on the Wheels of Zeus company before they launched a product. They did apparently license the technology to Motorola but nothing entered the marketplace. From that article I somehow made it to another article with some screenshots of the concept in action.
The concept of tracking individual objects with a localized GPS-type system is like shooting a fly with a cannon. The cost alone for the tags and central system was probably too cost prohibitive to be a reasonable product for the marketplace. I'm sure it would have gotten some legs but nothing necessarily disruptive as a technology.
What I'd like to see is Apple tackle a GPS unit design. In fact I speculate that within 5 years that Apple will get into this market.