Sorry I couldn't jump in sooner, but we have been very busy getting ready for CTIA and our big launch tomorrow.
One important caveat about recognizing drives with the REDFLY is that they have to be formatted FAT32, not NTFS (yes it seems strange to me that Microsoft would not support this in Windows Mobile, but...). Being an aspect of the OS, there is little we can do to change that unless we decided to create our own proprietary implementation, and storage is not a primary avenue for us to grow. We really have not done extensive testing in this area, but we have reports from customers about success with some pretty large drives.
Thanks,
Laurie
Director of Engineering
Celio Corp | REDFLY