I've developed a specialized software application for solving diagramless puzzles. Although it's for solvers and not constructors, it might be of interest to constructors who post diagramless offerings online. The software is available for free: http://blueherons.org/diagnil/
The user interface will probably undergo more fine tuning, but the current version should be useful to folks with a moderate interest in diagramless. It could also help attract new solvers who don't yet have an interest in this puzzle type.
Ben Di Vito