Presumably you can hook up either a USB or a Firewire device with a hub/adapter, unlike USB and Firewire which are incompatible with each other.
But having done so, will Thunderbolt support features of Firewire, like Target disk mode? Or the chaining of 63 devices? Support the peer to peer communication between Firewire devices if those devices are connected to a hub/adapter?
Will it support the 127 or whatever the number of USB devices off a hub/adapter?