DIHMRS
The (US) Defense Integrated Military Human Resources Management system (DIHMRS) was kicked off in 1996 with an initial target date around 2002 or 2003 (Wikipedia is incorrect about this) and the goal of providing an integrated personnel and pay system for all US military personnel. That goal was effectively met for the US Marine Corps in about 1975 or 1980 with the predecessor of the Marine Corps Total Force System; that IBM mainframe system was deemed "not scalable" from the ~200,000 Marines to the ~2,000,000 in all services - at a time when IBM mainframe capacity was two or more orders of magnitude greater than when the MCTFS predecessor was deployed.
Northrop Grumman, rather than IBM, had the contract for this one, but the vehicle, as here, was Peoplesoft, with a requirement to provide "some" custom logic for the immensely convoluted military pay and personnel laws and regulations. There was some mission creep, rather than the gallop described here, but it dragged out much longer. My branch and a few others were sucked in about 2005, when it was around three years late, to develop some of the custom logic. And help spend some of the money, to be sure.
By the time it was cancelled in 2010, undeployed and aged 15, DIHMRS had burned through around a billion dollars, $800M of it after Northrop Grumman got the $285 M contract in 2003. Part of the money went for IBM p-Series systems that were nearing obsolescence before being used for anything but maybe development. It was a mess.
The DoD IG report at http://www.dodig.mil/audit/reports/fy10/10-041redacted.pdf is mildly intereting to read and might be an outline starting point for a similar report on Phoenix.