I bet you just read the new Hot Rod, where they put a 65 body down on top of a 03 Cobra....Very cool article.
Of course it can be done....But the expense of doing just that mod for the sake of air bags will be very high. I've been out of the collision repair game for way to many years to know the current prices of components, but it will not be cheap.
Basically you would need to find a donor vehicle (a late model Mustang) and get the steering column with the steering wheel/air bag in tact....then you will need the sensor that goes in the front of the car, and the brain that usually mounts under the seat. (I think thats all the stuff you need)......Swap out the steering column (the hardest part of the job), then mount the sensors, and wire it up.....Now if you want dual air bags...you'll need to swap out the whole dash.
Hope this helps....And despite your request....I am still dieing to know WHY?