Catalyst has no dependence nor restriction on any data or view layer at all. No data layer? Fine. 100 data layers including 10 DBs, 5 caches, file maps, webservice calls, parsers, random generators, also fine. No view, fine (but stupid because it means the controller has to do output). 100 views coexisting -- TT to Mason to JSON to XML to LaTeX to PDF -- also fine. The M doesn't mean RDBMS any more than the V means HTML.