Well, if they were thinking like they were back then....I think they would probably have gone with the 717. Why? The 717 was designed precisely for what they were flying.....short inter-texas routes. The operating costs of the 717 can't be beat for that market. I don't think they would have gone for an airbus product, simply because the Airbus products are more plane than they would need (performance/range/other stuff). However, if they were thinking long term....the 737 is probably still a better choice because of the better range and capacity.
Interesting Question though....I would be curious to see what others think.