IcelandAir has a pretty cool offer that a few of my friends have taken advantage of:
"Icelandair has always offered cheap flights to Iceland but now only lcelandair gives you the opportunity to visit Europe's hottest destination, lceland, on your way to or from Scandinavia, Great Britain or Continental Europe for up to seven nights! And best of all, you pay NO ADDITIONAL AIRFARE!"
If I can ever get some time off, I would consider a stopover but the wife hasn't warmed to the idea. She met two of their "Air Hostesses" in Mexico and one felt the top of her Bikini was too "restrictive" - neither were wearing much fabric anyway. We were on a catamaran in the Gulf - Me, the wife, the guy who owned the boat and those two. I bet I still have bruises from where my other half kept hitting me.