If you're still recovering from the tenth anniversary fiasco and are looking for anniversary gifts for number eleven, you're not going to have too much of an easier time with this one unless you go modern. Maybe whoever invented anniversary gifts didn't expect people to stay married this long.
Your traditional gift for your eleventh anniversary is steel. Well, it's certainly generic enough a material. But most people, when they think of steel, think of men in hard hats putting up tall buildings and whistling at girls as they walk down the street. Well, believe it or not, there really are some nice anniversary gifts that are made out of steel.
If you want to go for the big guns right out of the Stainless Steel Kitchen Sink Guys you can always spring for a new steel sink for the kitchen. Of course this isn't something you just bring home with you wrapped in a bow that you can hand over to your wife. You're going to need to contact a qualified plumber, order the sink and then have him come and install it. You might want to pick out the sink yourself from an appliance store and have it delivered so that your plumber can install it. Either way, this isn't something that's going to be easy to keep a surprise.
If you don't want to go with something as big as a kitchen sink you can always go with something a little smaller. A perfect, if more obvious, gift made of steel is stainless steel kitchen utensils such as knives, forks and spoons. No, it's not very romantic, but at least it's a practical gift and something that you both can use.