I second separating the reader by touch and non-touch forums.
The non-touch devices have very similar interfaces, while touch devices have many things in common too.
I think keeping an Accessory, Dev Corner, and troubleshooting forum common to all Sony Reader would make sense too.
The forum front page would surely look much more tidy with just one forums per brand, but so many of us have Sony Readers and Sony now have so many devices in the wild that only one forum would be really confusing.
One also have to keep in mind that the Sony readers forums alone represent almost as much forum posts as all the others brands and devices combined (5466 Sony Posts compared to 6408 Posts for all the other E-Book Devices as of today).