For the record, I just tried this out myself yesterday and today (I was speaking from theory based on how I thought the iPod worked before - actually tried it on mine to make sure yesterday
) and it works great.
I'm still working on beginner lessons, so I created a smart playlist with the following criteria:
[match all]
Author contains JapanesePod101.com
Name starts with Beginner
Name does not contain S2
After it generated the list, I noticed the order was a bit scrambled. Sorting on the name didn't work because some of the episodes listed the episode number slightly differently. Then I noticed the Track Number field was filled in with the episode number on *most* of the episodes. There were a couple that were missing this, but it was few enough to do a Get Info on each of them and add it manually. I then sorted the list on the Track Number field.
I then dragged that playlist onto my iPod. The act of dragging that playlist onto the iPod took all of the matching episodes with it, whether I had already listened to them or not. My first normal sync afterwards deleted all of the ones I had already listened to off the iPod.
What this really works good for is the News episodes of course. Been spending the last few days listening to the last year and a half of news to get caught up on what's been going on around here since I'm still a newbie.
Using the playlist method list this plays them all one right after another, and they still get marked as played in your podcast listing next time you sync (and then deleted off the iPod).