It is coming.
Canon wanted to see if you would buy a Non IS version for $2200 before they release a $3500 IS version.
It would have been hard to go from a $1400 version 1 to a $3500 version II IS. Much easier now that they have you prepared.
Canon does estimate the selling cost, and includes it when deciding which version to produce. They also have pro's evaluate the prototypes and see which one they prefer. While a IS version might be preferable on a consumer grade crop body, its not necessary on a FF body. The 17-55mm IS is the equivalent crop lens.
I've used mine now for thousands of shots and never missed IS at all. Only when I get to about 200-300mm does IS really become a help. I don't see any need for it on my 135mm L either.
However, if IS sells, it will happen eventually, but not soon, since Canon is not pushing out new products because of the economy. The 70D is a good body, but its not selling, people are hanging on to their pocketbook.