Being a mapper, I am both frustrated, and grateful at and for displacements. They're a great piece of cliff-engineering technology, and have many other uses as wire fences, smooth curves and hoodoos. And yet the tools for which they are made are relatively limited. No snapping, a buggy smoother, raise-to that doesn't work, and little beyond sew, subdivide and overlapping can prevent leaks. Now, while I haven't found a solution to any of these, I have found the possible means to find one. In the sourcesdk/bin/orangebox/bin/filters folder, there lies the displacement tools, highly editable yet hidden away. There lies a txt file, dspfilters, which contains the information to every displacement tool. With it, you can add tools with different effect, applications, or just create funky patterns. Unfortunately stability is not its strong point, so use with care. I've thrown together a few basic (and not to mention, buggy) examples, and I hope you guys can find something useful to do with it!
http://www.mediafire.com/?zhimmdw53d5
http://www.mediafire.com/?zhimmdw53d5