Gemse 1.0.16 has been published!
The project Gemse has been started in the need for an editor for mathematical formulas that is fast and can be controlled by keyboard only.
Actually, the first approach to this problem, "Gemse Approach 1", is an editor for Presentation MathML, Content MathML and OpenMath. It is currently in development.
The second version of Gemse is being planned. It will be a complete reimplementation and it will be capable of editing whole HTML and OMDoc documents. Gemse 2 will likely not use Mozilla and its ever lasting enforced updates, breaking APIs, and JavaScript imposition.
You can find other solutions on the software list of the W3C.