Is there any way of identifying if there are two sd-cards in a device??
Edit:
I have found that at the moment, there is no way of distinguishing between internal storage and true external SD card. In some devices like Samsung Galaxy Tab (7 inches), the system takes the internal storage (usually 16gb) to be as an external storage. Unfortunately there is no way to distinguish between internal storage and secondar/external/sd-card storage. If someone thinks it is possible (for honeycomb and previous versions), write here and I'll prove it.
I don't believe there is a way to check for dual sd-cards, but some devices do have 2 types of external storage. For example, I know on some motorola devices, the internal secondary storage is accessed with /sdcard-ext. You could check to see if this directory exists (I know that other devices with secondary storage also use the -ext append) and react accordingly.