Calling All Javascript Experts

We're looking for a highly skilled Javascript developer with lots of experience using frameworks like backbone, ember, etc. to advice on which one(s) best suit a new web interface application we're building. We're developing a desktop based interface (no mobile or tablet or app).

You must have experience creating high performance web interfaces, preferrably ones with data grids.

You will be given the requirements of the interface we're trying to build, as well as shown similar functionality from other tools, to best illustrate what our interface needs to do.

You will need to advise on:
- the pros and cons of each framework.
- how its functionality fits in our interface.
- why it will help achieve our goal of performance.

We prefer to go through this over skype (using screen sharing), hence no need to write up recommendations, etc. Probably an hour of your time on skype would be enough.