I've been working on a batch uploader the past few days. It's at http://tonyfox.ws/e621.php

If anyone decides to use it at all, just keep in mind that it'll take a while to submit all the posts (takes me ~1 minute to submit 10 posts, and i'm running it locally).

Until Arcturus gets a better account system going you'll have to go into your e621.net cookies and find your pass_hash cookie and use that on the upload form. It's not a secure connection or anything but the hash isn't saved in any permanent form (just in your HTML session) and I won't ever see it, and if you don't believe me, you don't have to use the uploader.

Oh, and this site's only running off my home connection so it might get slow if more than a few people decide to use it at once :D

I've updated e621:tools. Wonder if this sort of thing could be coded as a greasemonkey script, extending the existing upload form?

There, I added a form for setting number of posts, to specify whether to use remote image URLs or local files, and the default tags/source.