How are you defining "netbook?" The original definition is basically something really small, really cheap and really slow.

If Ivy Bridge is inside it, then it can't be really cheap or really slow.
If you're willing to pay more, you can get (or will be able to get) netbook-sized units with Ivy Bridge in it at prices higher than traditional netbooks.
For instance, I have a Samsung Series 3 notebook that many would consider a netbook. It has a ULV Core i3 Sandy Bridge with HD 3000 graphics, an 11.6" screen and weighs 2.9 pounds. However, it also has an MSRP of $700.