generalized n-categories?

Not quite so. The n-Lab contains a page on it: http://ncatlab.org/nlab/show/hyperstructure , but that is not that new. The usual deficiency of such constructs (and the many attempted definitions of n-categories) is their reliance on set theory. Grothendieck seems to have been the first to suggest to forget set theory as foundations, and Voevodsky's way to build a homotopy-theoretic foundation of mathematics on some sort of computer language (leading to entirely new approaches to artificial theorem proving/checking): http://ncatlab.org/nlab/show/hyperstructure may be interesting for Baas' ideas too. Interestingly too, homotopy theory, n-category were caused by attempts to deal with topology, and Baas' concepts come from the same background. He was apparently motivated by Charles Ehresmann's ctitique that n-categories should be insufficient.