These aren't adventure ideas exactly, but things that have popped into my head over the last couple weeks that I've played.
Home Sweet Sewer: You know this one, solo mod where you have to lead some dogs out of the sewer without killing them (take off any guard items!) Scrag, the quest-giver, strikes me as a nice kobold who will go onto to find himself in more trouble throughout his life. Trouble that only bold PCs could take care of. Heck, you could make this a small low to mid level saga that starts with Home Sweet Sewer.
Stopping the Sahaugin: Under Korthos is a creature of terror and myth, an ancient terrible monster that is kept in slumber. When you start your adventuring career, you help keep it asleep. But what happens when simply readjusting the mechanism isn't enough to keep the creature down anymore?
The Sands of Menechtarun:
There's a road in this wasteland that is underwater. Where did it go? What's there now?
There's also a collapsed entrance tucked away in an obscure corner of this desert. The door shutting doesn't mean whatever was in there died. . .