Not the gp, but I believe the idea is to stop displaying long columns of code like so much wallpaper and instead treat it like the directed multigraph it actually is.
I don't know. I don't think it exists yet. But have you ever seen an expert using etags/search/debugger/etc to bounce around a large codebase? The location of the functions in the file hierarchy doesn't matter at all. The important graph --the important graphs-- are latent in the code itself.