WM6.0 and WM6.1 both allow you to keep typing and it will be broken into two messages when you hit Send.

If you don't have WM6.0 or 6.1, this may interest you quite a bit since 6.1 now has the Threaded Messaging:

I created an updater by combining the Sprint 5.0 Updater with a 6.1 Rom!
(And this is the true 6.1 and not 6.0!)

This updater works for any carrier since it does not affect the provider radio settings, it upgrades the Operating System. I removed the Sprint Radio Settings, so your current carrier settings will stay put and not be affected by the upgrade!

Example: I have Sprint for a carrier, whom didn't even provide a 6.0 upgrade I may add, and I am running 6.1 on my phone now and am loving it even more!

Basically all you do is format an SD Card to Fat32, copy my files to the SD Card and upgrade your phone using the SD Card method. (I provide step-by-step instructions on how to do it.

I do charge only $10 for the upgrade, a minor price to pay for all my work and to have your TREO 700wx (any carrier!) running the latest and greatest OS!

So for only $10 and about 15 minutes of your time, you can upgrade your 700wx to Windows Mobile 6.1!

Download it here: Windows Mobile 6.1 Upgrade for TREO 700wx