Plug-in Prius spare tire options?

The only thing that I really do not like about my 2012 Plug-in Prius is that it does not have a spare tire, nor does it have a well where one could be stored. However, for some reason the car does come with the usual tire changing tools - neatly encased under the driver's seat.

I don't so much mind driving around San Diego without a spare (in case the car suffers catastrophic tire damage) but I do not want to go on a long trip without a spare tire. The last thing I want to do is find myself stranded in the middle of nowhere without a spare tire and miles away from a tire store and help.

Does anyone know if there is a space saver tire from Toyota that will fit properly on our cars (the same diameter)? If so, perhaps we can buy one and put it in a bag to protect the car and its contents on road trips. How much does one of these tires cost? Is there a tire bag that fits it well? That could provide a business opportunity for some entrepreneur.

As for using the provided pump and tire sealant, has anyone else read all of the cautionary warning statements in Toyota's owners manual? They just stop short of telling people not to bother using it. I, for one, have been sufficiently discouraged that I will probably not ever try to use it.