There is a tool - http://qt.nokia.com/doc/qtopia4.2/qtopiacore-qvfb.html#skins which allows to use predefined skins. But i cant find tool for skin generation. Does it exists or skins should be created manually.
This is a rarely used feature since QVFB is intended to be used only for testing during development of embedded applications so no tool exists. They have to be created manually. I doubt Nokia will create a tool for this, but I'm sure there are some people who would use it if someone felt inclined to write it.