I may post this on the mainboard, but I wanted to see what you guys think first.
Instead of trying to invent new ways to introduce items/spells/etc, I have an idea....AUCTIONS!
Step 1: Make an auction house zone in Jeuno
Step 2: Set times and dates for automated auctions
Step 3: Post what items will be up for bids
Step 4: Go at it
Not only will you generate a lot of continual interest ("Hmmm, I wonder what they've got up for auction next hour?"), but it's a guaranteed way to pull money out of the economy. Not only that, but it should make for some interesting conversations...
"Hmm...should I go to the auction and try for Dispelga, or should I stay here and protect this NPC from being captured. Gah, I hate you SE!"
Auctions.
Fin. :D