Found one by a trusted developer. Cache Cleaner
It will scan all of your apps and list them with their respective cache sizes. You can:
EDIT: Added the following
- clear all
- clear selected
- set the app to always clear when loading the app
- set the app to always clear cache on boot
It seems to require root. At least, it asked me for root privileges. I'm not sure, maybe it only needs root to clear cache of system apps, but those tend to be the ones that have the largest cache folders / files anyway....