I have a small and only mildly helpful suggestion to the issue. I don't know if anyone else noticed, but if you take HAPPYTREE's suggestion one step further, it makes deletion a little better. Here's how:
- Pull down from the top and hit select
- THEN select an item to delete
- ***NOW*** hold that first item and select the item at the bottom of the page
- Delete.
So now you're selecting multiple items. I still don't thing you can select anything beyond what you can see on that screen, but it's slightly better than tapping each individual message.
I removed my email address, set it up again with only 3 days of email, and did the above without too much trouble. Now it's just maintenence I guess.
Seems that with IMAP it SHOULD sync and archive/remove messages when you do that on a desktop client, but I don't think it actually does. Pitty.
Good Luck!