Perhaps other people have good answers about this. I know of no such programs. MIT, of course, used to host the X Consortium, but they now have no ties. And the X Resource and X Journal, magazines that covered X, have ceased publication, so I`m not sure how much research work is being done in X and Motif.

If you`re looking for a job using these technologies, you could apply for work at one of the companies which offers this software as part of an operating system. Or you can develop commercial applications, of course, or you can find universities that just happen to be using this technology in the pursuit of knowledge in other fields -- using X and Motif to test user-interface issues, for example, or using it to display the results of experiments, in just the way that this software was intended to be used, for many purposes.

Good luck.