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 and its lookalikes (notably GTK+, Qt, and LessTif) have 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. Until recently, there has been a scarcity of introductory material for Open Look in print (but O'Reilly's Open Books Project (http://www.oreilly.com/openbook/openlook/) now provides free on-line copies of three relevant books (a user's guide and two programmer's guides). Unfortunately, the Motif API, and those of its lookalikes, are vastly different from the XView API with which WAVE is written, and a port to Motif would be decidedly non-trivial.