I’ve always used the published-date for that. My usual published field (like at work) isn’t a boolean, it’s a nullable datetime field. If null then it’s invisible and that won’t change. Once published then it sets to ‘now’ so it’s visible and ordered with other datetimes in relation to that. Or I can set it in the future and it will be visible at that point. As translations are finished you can set them to all the same date if you want, but it might be useful to set a translation at a later date (like at the time it was finished) if you so wish so it gets ordered at the top of a language-specific ‘new’ page. 
I mostly come from web frameworks in C++, erlang, and I hate to admit it but PHP (it was paid work so eh…), never touched ruby to date. ^.^;
Heh, never heard of such a thing. Do you have a link of descriptions? I’m curious if there are ideas I can swipe. ^.^
