But I don't think the conversation here is about anonymity, its about side channels to discover the actual content of the SSH session. The OP is looking at determining the command typed based on keystroke timing. The attacks you link would work for any traffic that could be intercepted, SSH or otherwise, and they wouldn't give any info about the content of the stream.
If we're just focused on removing all traces of keystroke timing from the channel, then I think a decoupled SSH transport layer which is providing say 1kB of zero-pad every 20ms to the the shell to fill up, along with a FIFO to spread that out, and maybe some logic to ramp up and down the channel bandwidth based on queue length, you would go a long way to mitigating this specific attack.
If we're just focused on removing all traces of keystroke timing from the channel, then I think a decoupled SSH transport layer which is providing say 1kB of zero-pad every 20ms to the the shell to fill up, along with a FIFO to spread that out, and maybe some logic to ramp up and down the channel bandwidth based on queue length, you would go a long way to mitigating this specific attack.