Having read Dirk Hayhurst's excellent book The Bullpen Gospels: Major League Dreams Of A Minor League Veteran over the summer, I've had more than a passing interest in getting a few of Dirk's cards since then. They're surprisingly few and far between, in an age where everyone who gets a tryout ends up with about 300 cards, but I did manage to pick off a few recently on eBay.
2003 Eugene Emeralds team issue: this is, by most accounts I've found, Dirk's first card. Anyone with info to the contrary, please let me know!
2007 San Antonio Missions team issue: this card's really cool to have, because...well, I can't tell you. You might not have read the book yet! If you haven't, seriously, go get it! Mao! Diddy mao!
Aside from those, I've found an autographed Fort Wayne Wizards card, Lake Elsinore have him in at least their '05 and '07 sets (they appear to be out of '06, and I haven't tracked down a set anywhere else online), and there's a few limited issues from Freedom Card Board, who had Dirk as a guest during this year's National, but I haven't picked those off yet.
To the best of my knowledge, that's about it. No sign, at least at the moment, of Dirk's cards from Mobile, and he may or may not be in the '07 or '08 Portland Beavers sets, but I found nothing from the big manufacturers, despite big league experience in '08 and '09. I don't know about you guys, but I'd think he's a prime candidate for '11 Allen & Ginter, despite being out with an arm injury this year. His card would look great next to my Oscar Wilde and Machiavelli cards!
Of course, it's highly possible that someone else reading this has been more dilligent and has a complete (or at least more complete) checklist of Dirk's cards, or that Dirk himself has an accurate accounting of which sets he's been in (I'm giving him a buzz on Twitter as soon as I'm done writing this, to ask; I could do it before, of course, but then the conversation would already be over!), so if any of you (or Dirk) have more information than I've got here, please leave it in the comments!