I know lots of folks have added (helper) air bags inside their rear springs to help out when towing. What about air bag suspension set ups? With them inflated would they be capable of handling the extra load like the ones in the springs?
All modern big-rig trucks (Kenworth, Peterbuilt, etc) have air bag suspensions. So, at least in theory, towing can be done. This does not mean that the air bags marketed to Impala owners are appropriate for towing, but that the concept will work.