I saw once on my friends phone, which I think was the Sony Ericsson K850i, that he had his texts sorted by sender.

For example, his inbox may look like this:
Dad (16 messages)
Mum (54 messages)
Peter (29 messages)

Then he selects the name and it opens all the messages from that person.

Maybe I dreamed this but I think it was like that? Can somebody confirm?

If SE do have this feature, which phones have it?
any help appreciated!