This has been confirmed by TMobile, Samsung and Blackberry Connect, since I talked to them all today:

The t719 has a 1024 character limit for composing email.

Strange, I know. You can receive, reply to and forward full-length emails, but you can't compose longer emails. This is an issue with Samsung's OS, not TMo or BB, so it could be changed in an upgrade.

When you think about it, most emails we send, especially those on our phone are no longer than 100 words or so. This limit is about 150 words. So maybe it's not really a limitation for most. I considered taking the phone back, since I'm still in my two week tmo-guaranteed honeymoon. But there's a lot to love about this thing. It's got a low geek factor, which is kind of nice after carrying a Psion, Palm and BB for so long.

Kevin