I second that. I am going to take the GRE in the near future and would find this to be extremely useful.

I would love that so much. I am studying for the GRE now and I am using the math sections to brush up but I would be thrilled to see something that is directed at the GRE specifically.

It would be wonderful to have a mission dedicated to material on the GRE. I'm currently going over the algebra and geometry content, but there's quite a bit of it that isn't necessary for this purpose, and although I'd quite like to study that independently, I've only got a few weeks and it would be very helpful to have a prep mission for the quantitative section.

My further arguments in support of this idea (which, I can understand, require a new investment from Khan organization) are based of the following facts:
1. the video lessons in maths are really-really good! I have seen other videos on maths in internet, often on the same subject, sometime not free, still I haven't found as very good lessons as the ones delivered by Sal; they are also good because they gradually move from the simple to the more complex, step by step, without assuming basically anything (the only thing that I would try to find a way to implement is a "quick link" to other subjects that are related or they are cited in the video played, and that are not with in the set of videos to which it belongs)
2. the videos dealing with the subjects are usually more than one, with different examples and a different ways to approach the same issue. This variety is very good for learning.
3. the videos are not so long and they are associated with exercises to apply the concepts learned: I would even add more frequent opportunity of exercises to increase accuracy in solving the problem and, may be, speed in solving them because in tests (SAT, GRE, GMAT,...) also speed is required in the performance.

So, Khan Academy has a huge potential to offer this kind of preparations for tests.
And if I had to pay, I would spend my money very well.
The best it would be to keep it for free, but I can understand that there are costs to cover

There are a lot of people preparing the GRE, so if Khan Academy offers the GER Prep, it would be a big help.

ETS has a list of Khan Academy videos for the GRE quant questions, but it would be nice to have a Khan Academy mission all ready to go. In the mean time, we can manually follow this list: https://www.ets.org/gre/revised_general/prepare/khan_academy

Cheers,

Mark