That idea did pop into mind a few times, but I'm no real sprite customization guy. I'm just good at recoloring, and maybe adding one or two details, like say adding a cape or making elf or numan ears. I'm not good at making custom poses and animations sadly.
But, if someone could make the animations, I would greatly appreciate it.

And indeed, those sprites are just about everywhere, but here is one.
As you can see, the sprite to customize, would indeed do the job nicely, but there are no running, or proper jumping animations. Or standing and attacking sprites. Mostly this would be used as a base, and it wouldn't be a bad idea to recolor all of the animations.
In some picture programs, like the one I use, I can easily recolor all of them, and e-mail it to someone with great sprite making skills. Any volunteers?
[EDIT]
*FACEPALM* I forgot the vgmuseum doesn't like hotlinking. But I fixed it. I hope.