No. (Rant begins here.) When I designed WAVE, I attempted to use Motif, but switched to XView when it became clear that much of the documented functionality of the Motif toolkit (at the time, version 0.9) was unimplemented or unusable. It also seemed unlikely that anyone would prefer Motif's buggy, ugly, proprietary, bloated, kludgy procedural interface over XView's buggy, attractive, non-proprietary, streamlined, elegant object-oriented interface (end of rant).
Motif has clearly become the standard, however, and a consequence of this is that the Open Look user interface presented by WAVE is unfamiliar to many users. There is a scarcity of introductory material for Open Look in print. Unfortunately, the Motif API is vastly different from the XView API with which WAVE is written, and a port to Motif would be decidedly non-trivial.