All right, tablet received and most of the testing is complete.
The Phidgets drivers are installed and seems to be working as expected. The tablet itself is working well, very responsive at the moment at least, and I'm turning off "tablet mode" to use the desktop (and the phidgets control panel).
I've connected a small, powered USB hub to the tablet (using the computer/"uplink" USB port), and then connected keyboard, mouse and a Phidget TextLCD kit.
The LCD screen of the TextLCD kit seems to require a powered USB hub, but it seems it's only the background light being affected. If I pull out the power cable to the USB hub the light is gone, if I plug it back in it returns and the text is still displayed.
The powered USB hub doesn't seem to deliver power through the "uplink" cable, so I connected a USB splitter cable (where one end is connected to one of the ports in the front of the hub for power). The blue power light of the tablet then lights up, but after half an hour of testing (with the tablet screen off) it seems to use more power than it's able to charge.
I've then moved that cable to be connected to the USB charger which came with the tablet. This seems to be working OK, but I don't seem to be gaining any battery capacity - it just stays at the 45% it was before. It seems to apply both for "screen on" and "screen off" strangely. (I've tried appr 15-30 minutes with both screen states).
Having it not drain the battery is OK in most cases, but if there is a small power loss and it's not able to recharge back to 100% it would inevitably mean that we'd drain the battery and the tablet would shut down. I'll leave it on for the weekend and check back on Monday. If it's not working I'll try a USB charger with more juice.