Does anyone know if the TP uses Serial Port Profile to communicate with Bluetooth?
According to the device itself under Device Info/BT, yes.
the touchpad does support SPP yes. Map Tool Pro uses it to talk to Bluetooth GPS devices.
Bluetooth keyboards are only supported in HID mode - you can pair SPP mode keyboards but can't do anything useful with them (the complete opposite of Android)
2 TouchPads and a Preł