iRobot just announced some new Roomba vacuums and they feature interesting capabilities. The Roomba 205 DustCompactor Combo Robot is being advertised as "the industry's first onboard mechanical debris-compacting system." In other words, it squeezes dust and debris together like, well, a garbage compactor.
This allows users to go eight weeks without having to empty the vacuum. It also eliminates the need for a dedicated debris bin.