Eternal Wands is what you're probably thinking about. They're in the Eberron Campaign Setting and reprinted in MIC.
Only problem with that is that they can only store up to 3rd level spells.
Scepters might work though (Lost Empires of Faerun). Still, if you want an 'infinite' supply, you'll have to come up with a way to use one without actually consuming a charge.
There are some tricks for stuff like that IIRC, but I'm AFB right now, so I'm not entirely sure.
As for Shapechange, I'm not sure, but there might be a Staff with that somewhere?