First of all let me paste a link to the Wikipedia.
Business models for open-source softwarehttp://en.wikipedia.org/wiki/Business_models_for_open-source_software
One of the companies who offer Supported Open Source Software is Australian based Squiz ( http://en.wikipedia.org/wiki/Squiz ). Support packages costs a lot of money. They mainly target large organizations funded by government e.g. universities. They're clients need solution for hundreds of CMS users with complicated permission system (confirmation can be found on their development blog http://www.squizlabs.com/ ). If you ask them they can provide a priority bug fixing service.
I suggest Spirit developers to think about going similar way. Of course on a small scale.