I have no information on the MindCad format itself.MindCad can currently only export and import mind maps via OPML. OPML is a flexible
(some say loosely-specified) XML schema designed for recording outlines. It therefore
carries only a subset of the information required for a mindmaps.
The publisher of MindCad say that they are in the process of switching to a more complete
XML schema.
Anyone using this to make an XSLT for conversion to other software is invited to submit
it here for general use.