[MENTION=25737]Kaz-kzukNA1[/MENTION] has djinned up a replacement, dig around on NSXCB.
If you search up on the size of the tire, there are places that have it listed for sale.
What's amazing is that I've been around so long that parts that people used to give away (such as stereos, air pumps, and spare tires) are now worth a small fortune. I've got a yellow spare and full 1997-2001 brake kit that I picked up for $300 that just sits in my garage.