......or those who are in the know:

Is it possible to switch a steering wheel and it's airbag to another model in the line-up? What if it was a different year?

I've got the "pie-plate" steering wheel in an '01 Ram and would'nt mind switching it with something off of an '07 Ram.

Is the airbag/clockspring, voltages, sensors needed all the same throughout the line-up and will work as intended?

it would probably work. but I would advise against it. just because it fits doesn't make it proper for the car.

in the beginning of car air bags they were somewhat universal. the early 90's Chryslers all used the same one.
on new cars today air bags are designed for specific cars. the weight and car structure are considered in air bag design. most of the air bags made today deploy at different forces compared to the weight of the drivers. sometimes the same car chassis was revised during the life of the body style. I have found the front bumper reinforcements are different thru the years of the body style due to different designs of impact forces. also I have experienced the 1/2 ton trucks use different air bags than the 1 ton truck of the same design.

Great info and advice MrT, thanks! I figured I'd be on my own with this one, so will have to think this through to see if it's worth the risk.

I found a picture of someone who did it, but no description or anything to go with it.

I agree with "MrT2U" and I will add I remember certain year Jeeps I worked with actually used what they called a mechanical fired type of air bag on the steerimg wheel as I know that one wont work on most any other car. I would also advise against it but it may work on some. Ron