I'm sure you've seen this link on the board.
http://www.miata.net/garage/align.html
I called some of the Arlington Firestone's a few months back and was asking about their "Lifetime Alignment". IIRC one of them told me I could sit in the car, provide my own specs and still get the Lifetime deal. I think the cost was $120-130. An alignment has been on my to do list. Anyone else interested in the Firestone deal?
UPDATE: The Firestone below will let you sit in the car, provide your own specs and get the lifetime deal for $139.99. I spoke with Mike.
Firestone Tire & Service Center
1233 Melbourne Rd
Hurst TX, 76053
(817) 595-1866