There are a few other Honda cars that are built on their Global Small Car platform:
The Fit Aria (City)
The Fit Aria, or City as it is called in some markets, is essentially a 4-door sedan version of the Fit. Besides having a trunk, it has a different front end with a less raked nose and a very "Acura" looking grill. The dash is the same as the Fit, but the center console has a cig lighter, pull out ashtray, and a coin tray with a sliding cover.
If the Fit Aria/City is a sibling of the Fit, then the Honda Airwave is a first cousin. You can look at the Airwave as a station wagon version of the Aria/City, although the two looks nothing alike. However, the Airwave does share with the Fit and the City the "magic seat" system because it also has its gas tank located under the front passenger seats. What I love about this car though is the "Sky Roof"; an enormous glass roof that covers the entire front and rear passenger area of the cabin. Even if you had the money, I do not believe the Airwave's roof curvature is the same as the Fit, making a retrofit near impossible.
The Mobilio /Mobilio Spike
The Mobilio (above) and the Mobilio Spike (below) are like the Fit's second or third cousins. They share the same chassis, but not much else. The gas tank location is more traditional in these cars, so no "magic seat" configurations are available. The Mobilio is a 7 seater with third-row seating for two, while the Mobilio Spike has no third-row seats, and no rear quarter windows. It also has a different front end that's less "robot" looking.