First, release date: consumer release is highly likely this holiday season. How do I know? It's obvious. They don't release it before Win10 official release (which is probably Aug. ~ Oct. time range). They can't release it after 2015: Imagine you are in charge in msft, you announce a big breakthrough technology that you are working on in last 8 ~ 9 years. Then you release it a year later. You give your competitors enough time to steal it or part of it before you release it. This is something illogical. If you look at the Wired article, the author was shown the exact same prototype last Oct. He has been on NDA since then, only publish the article two days ago. I think the product is ready and they are not showing the product to anyone. Win10 is what holds it back. However, NASA is getting it in July, I don't know how that workout.
Second the cost: It is a consumer product (they have said that a couple of times). My guess is $500 ~ $1500. Over $1500 doesn't make sense. They have said this is a platform, not just a device. For anything to be platform, it has to have user base, then devs come in. So I think under $1000 is very likely.