How to build your own Ultrabay Plus device
The UltraBay Plus Device Carrier is basically a tray with a proprietary USB 1.1 connector. Hence it should in theory be possible to transform any USB 1.1 device into an UltraBay Plus device that can be used together with the UltraBay Plus Device Carrier.
It is merely speculation, but in fact it looks like the connector of the UltraBay Plus Device Carrier's connector is the same as the one used for the UltraPort. This needs to be verified.