Nemo - We do have a MW Testers wiki, as well as a testwiki that you're more than welcome to play with :) http://mediawikitesters.orain.org and http://testwiki.org. We're also on IRC #orain (freenode)
We do allow for custom domains as well - hence the TestWiki. We also have another like SpiralWiki which is http://spiral.wiki
The farm is set up and managed openly. Everything is visible on GitHub - https://github.com/Orain
At the moment we don't run Parsoid. It's on the table and we haven't incorporated it yet with our current farm as we're going to be moving to either a different long term host or purchasing our own servers and all of our time has been focused on that. At the moment we're running off of several servers (aka prods in github) and are with DigitalOcean.