The one lady I know who had bypass lost a ton of weight and had the loose skin issue. When she had kept the weight off 5 years, she went in and had plastic surgery to tighten up the skin. She has maintained the weight loss for 15 years now. I'm sure it's not always easy, but she has done it.
Personally, I'm not a big fan of drastic surgeries, but if you can't get the weight off any other way, it's probably worth it. Of course there are risk factors, but there are major risk factors to being overweight, too.
Good luck in getting the weight off no matter how you decide to do it.