Just to be clear, XOWA isn't an installer for MediaWiki, but it's own app. This allows it to avoid the dependency on the entire MediaWiki tool-chain (apache, php, mysql, MediaWiki). Unfortunately, this means that XOWA has to reproduce the same logic, which is quite a challenge...
If you're interested in going this route, you can look at http://www.nongnu.org/wp-mirror/. This should build a local MediaWiki instance with one click. Keep in mind that it's a bit slow: it takes two days to build simple.wikipedia.org with images. In contrast, XOWA sets this up in about 30 min
I was already pretty far along with my own parser before Parsoid was usable though. (and my parser has its own DOM / hooks)
And I thought ah yes 'Outer Space' that could be another location an offline version could help.