The idea of some form of conditional formatting in Provision was being discussed as far back as 2007 when I 1st started using ProVision seriously.  It was apparently on the product roadmap at the time.  Unfortunately four years later we still don't seem to have any conditional formatting (although there is some confitionaing formatting in some of the process modelling).

Now I have no idea if this is actaully on the Provision product roadmap or not but surely by now conditional formatting would have to be one of those hygine factors for a modeling tool - they have to be able to do this. 

The obvious candidated for changing the style format of an object or link would be status, however Provision implements status as a separate object, accessable as a tab only on objects that have been deemed worthy of a status.  So technology has one, capability does not.  This could be addressed if the status object tab could be added to objects, and links including custom objects and links, however object based control of the status values that apply to an object would also be required (another idea I've raised here).  

Another approach would be some form of indicator that could be shown on or with an object, that could be linked to a status, or perhaps any field, with some form of definable colour or icon per value.