I created whereisscihub.now.sh a while ago for exactly this purpose (but limited to the subset of Sci-Hub, of course, and it used Wikidata as its data source).

I created whereisscihub.now.sh a while ago for exactly this purpose (but limited to the subset of Sci-Hub, of course, and it used Wikidata as its data source). It has since been taken down by Now.sh. Just as a heads-up of what you could expect to see happening :)