Haha, well I got sorta lucky - I got rear-ended and insurance $$ bought my bumper. I still have the dent though, but that's a good trade off IMO.
I still wheel mine a lot and will until the end, but I don't have the bumper yet so we'll see how the frame holds up. I'm not worried about it, lots of guys have swing-aways on their 3rd gens. The tow package is intended for a lot more tongue weight and stress than a swing-away will ever put on the frame. If I planned on towing with it a lot I would probably reinforce the frame a bit.
The 3rd gen's frame isn't boxed for the last 2 ft. or so which may be why they say it's not as stong as the 4th's (I'm not sure, but I don't think the 2nd's is boxed in the rear so I doubt it's any stronger). The 2nd's factory swing-away was body mounted so that's definitely not as strong as mine will be. Regardless, boxing the rest of the frame wouldn't be very hard, or you could put a cross bar type of thing to beef it up a little if needed (in fact IIRC, that's what Chaplain did - the guy whose pic is at the top).