mwlib has a "virtual wiki" concept: this is just an abstract API, which describes how articles, templates and images are retrieved from a MediaWiki. mwlib currently provides 4 implementations:

mwapidb (mwlib/mwapidb.py)

mwapidb downloads needed items via HTTP from a running MediaWiki instance utilizing the  MediaWiki API.

netdb (mwlib/netdb.py)

netdb downloads needed items via HTTP from a running MediaWiki instance.

cdbwiki (mwlib/cdbwiki.py)

cdbwiki uses a constant database for storage of articles and templates. A cdbwiki can be created with the mw-buildcdb tool from a MediaWiki dump.

zipwiki (mwlib/zipwiki.py)

zipwiki uses a ZIP file for storage. A zipwiki can be created with the mw-zip tool.