does it make sense to create UX deliverables about wireframing information design, when nowadays we are evolving to adaptive web design, with more than 2 or 3 different layouts for different devices? how is your approach for deliverables?
One approach is to build a complete set of wireframes using the "default" - or most highly-trafficked - screen size, then show representative examples in the other screen sizes you have designed for.
If you have a few common screen patterns, you can probably get away with showing an example (or two) of each pattern. For any interesting one-off screens, you should probably also show these at multiple screen sizes.
All of these decisions depend on the desired fidelity-level. Early in designs, when you are getting initial feedback and expect to change things quite a bit, I would lean towards fleshing out fewer screens and leaving more "undesigned" details in the interest of faster iterations. The more final these are, the more you need to pin down the details.
Firstly, I just want to say that adaptive and responsive web design are two different things. Adaptive design is essentially responsive design without a fluid grid/images.
At my shop, when we build responsive sites, we build the wireframes in HTML/CSS/JS with the actual breakpoints, then move onto visual mock-ups (6-10 JPGs for review: two pages of the site with all breakpoints), and then into dev.
We charge more for responsive design because it takes longer, requires much more thought, and is generally much more difficult to design. When comparing to a fixed-width design, typically we charge about 1.5x more for responsive design.
The purpose and value in each deliverable doesn't change whether you'd doing a fixed-width or responsive/adaptive site. They're still communication tools and clients expect to see them. Responsive design is but one approach to designing for mobile experiences. It is (in my opinion) the best approach and therefore the client should expect a markup.
Build your wireframe in HTML, and make it responsive.
Then you're set.