This site cruciverb.com has a similar feature (Puzzle Database). Here you can actually see the grids (not just a list of answers/clues). I believe you have to have a paid membership to use this, and it only covers a limited number of publishers and isn't always up to date.
I realize the post I'm replying to is more than four years sold, but here's my take:
1) The cruciverb database may not cover all publishers, but certainly more than one (vis-a-vis xwordinfo). They include NYT, LAT, WSJ, Washington Post, Universal, New Yorker, Crossword Nation and more.
2) The database may have had periods of being out-of-date years ago, but I have made sure it is updated on a very regular basis for some time now. Do a search and see for yourselves!
The cruciverb database search allows you to enter full or partial entries while specifying "Thematic Only", so it's fairly easy to see if your puzzle's theme has been done before (or recently) in the major publications.
-Kevin