FYI - There is a killer deal on a Miata steering wheel on eBay. The wheel is $39! Looks like it is in okay condition. Might just need cleaning.
http://cgi.ebay.com/ebaymotors/MAZDA...#ht_573wt_1591
Buy one of the airbags and you are good to go for under $200 total. That would be a steal.