XmeshNK 1.3.4.59074 is now public! Contact Sales to get a download link.
Fixed in 1.3.4: Filenames without frame numbers now work, and default to “single frame” loading mode.
Announcement: http://www.thinkboxsoftware.com/news/2015/7/21/xmesh-nk-loader-for-the-foundry-nuke-released.html
Documentation: http://docs.thinkboxsoftware.com/products/xmesh/1.3/Documentation/