There are some books like this, although the one I have used is strictly in the realm of jazz. I have found it very helpful to use books like this with my students because I find that it is easier for them to improvise when they are already 'in the grove' and attuned to a particular style. Starting from a blank slate, even with a given chord progression, is much more difficult because many students just aren't familiar with the rhythms and melodic figures typical to jazz styles. When they are only responsible for a couple of measures, they can draw upon what they have just played (sight-read) for inspiration.
Of course, after saying all of this, I can't for the life of me remember what book it was that I had used in this format. I just turned 40 yesterday, so let's chalk it up to that.

In any event, when i'm back in the studio later this week, I'll do some digging around. Maybe someone else here has some suggestions as well.