I can't even begin to count the flats I had when I was doing delivery work.. I bought a new F150 in 1979 and went to work as a district manager for delivery of the Dallas Times Herald and I had 3 flats in the first week.. That truck attracted nails.

 

Thanks to all you owners who have pointed me toward a solution! I am concluding that we will buy a wheel and tire for our future Fit and figure out then how to take Brain Champagne's idea of modifying the floor to accommodate the width of the true spare. That should be manageable! I'm thinking a wheel such as the one made by Rial Flair should be a good match to the other four. Can someone confirm this? Here are the Specs:
Offset: 3mm. Backspacing: 5.16” Bolt pattern 4-100mm.; Recommended tire size: 185/55-16; Weight 20 lb.

 

Look over the mod before you commit. The spare slips under a fixed part of the cargo floor at the front, so the mod might take a little work. It may be no big deal, but I thought I'd mention it in case you haven't looked it over yet.

 

That part of the cargo floor is attached to the folding panel, the whole thing comes out (couple of snaps) when you're supposed to put the full size tire in during a flat tire change.

 

Always wanted to do that wih the Element, but I was afraid creating even more wind drag!

It would definitely be the most unique attachment on a vehicle since the day I saw a Toyota Avalon with a Brush-guard.