This would also be very beneficial for clients, because if the feds can not locate the hidden service to put it under surveillance, they can not complete an end to end timing correlation attack against clients, even if they watch the clients sending and receiving traffic. some potential things to consider: 1. The latency of the hidden service will be roughly doubled as the circuit from the hidden service is doubled 2. There may be some anonymity problems with reusing nodes between the two instances of Tor, although I suspect this is less serious a concern for hidden services 3. There may be a fingerprint left in client entry return traffic as the response time after sending traffic will be uncharacteristically high, although cover traffic going down the same circuit should muddy this, and it really beats having a hidden service that can be traced in a day and then watched passively to complete 50% of an end to end timing correlation attack.