Good day, ibcdennis,
Thank you for posting your question on the Chinese Dedicated iPad Forum. Although I don't have any knowledge about this WiFi Storage devices, but I think the readers over here will try to help you as much as they could.
According to
Joseph Moran, External WiFi based storage devices can be a good solution to solve the limitation of internal storage for iPad, iTouch and iPhone.
Because we can load the device with the media (from a PC/Mac via USB), carry it around and then connect to the device via Wi-Fi (and a special app) when you need to access its contents.
And Joseph did recommend a few products:Seagate GoFlex Satellite, G-Technology G-Connect, Kingston Wi-Drive, Wearable AirStash, and last but not least the one which used by apanek , PogoPlug Mobile.
However, Joseph also highlighted that the wireless signal range can be limited so make sure that you keep storage devices close to the streaming place (e.g., an adjacent room may be too far away). Besides, different product may make the user not be able to access the storage device’s wireless network and a hotspot for Internet access at the same time.
Hope that this will help.