Anything that depends on lesstif should work with OpenMotif (but not vice versa).
I always use OpenMotif in Fedora. I always uninstall lesstif, like this:
rpm -e --nodeps lesstif lesstif-devel
Any app that claims to need lesstif has always worked with OpenMotif. The ones that claim to need a specific version will work by just creating an appropriate symbolic link to the libXm.so library from OpenMotif.
You can get OpenMotif RPMs for Fedora here: http://www.motifzone.com/filebrowser...otif/2.3/2.3.2
The ones for F10 work in F11.