Screaming Frog does do this. It has been what we use to find missing alt's now. I think it would be a great thing for Moz to add to the crawl report, or do a crawl for this specific reason.

Lawrence - you can use the crawl report to see meta description info, titles, response codes and more.

I am looking to find all the missing alt tags on my site at once. I have a FF extension that use to do it page by page, but my site is huge and that will take forever.

Thanks!!