Apply--
now! Don't give up. Note: Looks like you will need a city or state issued disability placard. A doctor might be able to help you get one. I don't know the standards for these placards, or whether you have to have the placard actually issued to you by the 31st. But inquire! If you get approved, you can still take time to make up your mind as to whether you feel comfortable going. Those with disabilities may actually (with approval from the event) drive around Black Rock City, at 5 mph in a car that has passed inspection, etc.
Disabled Persons Vehicle Application: Open until
July 31, 2011 at 12:00 noon, Pacific Time
http://forms.burningman.com/dmv at burningman dot com
Also, if you can stand (I don't know if you can) what about a small, low-power scooter?
Scooters and Go-Peds
Large, seated, street-legal "Vespa" type scooters, like motorcycles, are not allowed to drive in our pedestrian and bicycle city.
Small motorized scooters (two wheeled, lightweight, standup, small, no-seat, off-street type) and go-peds are allowed in Black Rock City but they are subject to the same rules as any other motorized vehicles - drive 5 MPH and have front and rear lights at night. BLM Rangers will issue citations for non-compliance.
Found that 2/3 of the way down this page:
http://www.burningman.com/preparation/e ... afety.htmlI have to admit, if I fractured my foot, I'd probably still go.

But that's a pretty personal decision, and you have my sympathy.