There seem to be literally dozens of comments on my Matrioshka Testing Question, so I was wondering if a community wiki format might not be more appropriate. If people here agree, how would I go about doing that?
To address the specific question:
What I see there is a lot of discussion in comments, which isn't really what comments are for. Community Wiki would make it easier for people to collaboratively edit the question, but these comments aren't proposing edits or asking clarifying questions, so I don't see how that would help.
To address the general question:
We don't generally convert questions to community wiki because doing so would also convert all the answers to community wiki, which would deprive those users of the reputation points for their contribution. That is one of the reasons the feature has been largely deprecated. See The Future of Community Wiki.
But if you want to convert an answer (that you posted) to community wiki, edit it and check the "community wiki" box below the edit textbox (on the right).