In a recent episode of a podcast called Security Now (#493: Tor: Not so Anonymous), they claimed that traffic can be delayed in unique ways to identify which client IP address on one side of the Tor onion is communicating with which server IP on the other side. So basically they insert gaps in the data transfers and look for gaps going to client IPs. Somehow or other Cisco's Netflow feature is involved.
Here's an idea:
To solve this deanonymization problem, why not have Tor clients simply always be uploading and downloading packets at a steady beat e.g. every 10 milliseconds, regardless of whether any meaningful data is really being sent? Of course the exit node would have to play along with this charade, accepting and sending packets even if there is no need. The tor process running on the client would have to be able to drop incoming "dummy" packets, as well as send them; same for the exit node's tor process.
Would this fix the Tor deanonymization problem?