A classic tech dream: Reinvent every facet of an existing business, from top to bottom. The personal computer industry was built on the impossible dream that there would one day be a computer on every desk — an example which inspires countless attempts to reengineer the virtual world. Most prove to be expensive busts. Like the air-taxi business. Eclipse Aviation, which made small jets which its backers hoped startup airlines would fly from point to point at a cost lower than private jets, failed to meet payroll last week, and only now has scraped up financing to pay its employees.Vern Raburn, the big dreamer behind Eclipse, left the company this summer — a condition without which the company would not have raised a round of financing. He had envisioned Eclipse building fleets for countless air-taxi operators, which would operate from new, small-scale airports — a whole new air-taxi economy, dreamed up from the ether, which he would monopolize. DayJet, the most notable air-taxi startup, shut its doors in September. But Eclipse failed not just because all the component pieces of Raburn's vision failed to come together. It would be easy, surely, for him to pin the blame on operators who didn't deliver on their part of the bargain. It's not clear that there ever really was enough demand for the service in the first place. As much as people complain about commercial air travel, the major airlines move millions of people a year, at a cost its customers pay, albeit with grumbles. Asked how large the air-taxi market would be, Raburn told a magazine in 2007, "The only thing you can say about predicting the size of new markets is that you will be wrong." Give Raburn credit: He was right about that. (Photo by AP)