Frost_Angel, first let me say I set all my Wordpress feeds to excerpts instead of full feeds. It's cut way down on scrapers for me.
Second... it's actually possible you've got it backwards here. Whenever I've had scrapers outranking me, I'm convinced it was because Google was unhappy with my page, NOT because they mistook someone else's page for the original. If your articles are years older than your scrapers, it seems unlikely Google could be confused about who's the original author on so many of them.
I have a page that used to be #1 for ages in Google, but after Penguin it now gets outranked by scrapers. So I think sometimes it's part of the penalty, or maybe a byproduct of the penalty, that they let scrapers outrank you.
Now, by no means am I saying don't send out the DCMAs - I send them out myself. I'm just saying the outranking might follow the penalty rather than the penalty following the outranking. So, if you get all those sites removed - and DCMA can do that - then you'll be ranking best for your text snippets... but it might not help with your overall Panda issue. :/