Unfortunately, no — Area 51 recently surpassed 10,000+ proposals across a broad array of subjects, but about 97% of them have been ill-founded or poorly supported efforts (97% is not an exaggeration).
When folks started rejecting proposals on the basis of "we've tried this before", it was decided it was best to wipe the slate clean with each failed effort. For the tiny, tiny sliver of content that might actually benefit future efforts, there was simply too much noise in that signal to let folks stumble haplessly into (and re-engage in) long-dead conversations.
If your subject is a good fit for a Stack Exchange-style Q&A, and you already have a community organized, ready, and eager to build your site, the chances are that previous efforts will have little bearing on a proposal with a stronger foundation. Any problems regarding previous efforts or general network compliance will be handled through hands-on moderation early on.