@larsoner said to open an issue to discuss this, since a new GUI is pretty major maintenance but @adam2392 @jasmainak and others (me) have expressed interest in incorporating this where it would be high quality and have a lot of users as a part of mne-python. I have a manual version written using PyQt5 but it's too slow and Eric suggested a VTK embedding would be much better. This is based on the img_pipe code (cc @libertyh) but has been rewritten and Liberty and Eddy Chang expressed that they would be interested in migrating it into a mature community.

Basically, the GUI would either have users input file paths or navigate using buttons to an MRI, CT (coregistered) and ieeg data file (and optionally a pial surface from a freesurfer recon which helps with ECoG) and then navigate in 3D space to each contact on an electrode/grid and select the channel that corresponds to that location. I'm currently working on a local_max algorithm that almost works that could help make it less work.

I think the main question is whether this would be a good fit in mne-python? cc @agramfort