I have to agree with the original poster -- it's sort of crappy and well worth a complaint.
I thought the French maid comment was funny and endearing when so much snark about house keeping entered this thread.
What I'm doing now is switching my life over to Google Voice. It seems that's a way to manage SMS messages a little better and more inexpensively.
Meanwhile, I wouldn't recommend wiping out the phone without first backing things up. Not the text messages, but everything else. There's an app for backing many application settings up that's not free, but if you're doing a one time wipe, you can back up and restore to try it out and then request a refund from the app store.
A lot of settings are magically backed up and restored by Google if you wipe a phone and keep the same Gmail account associated with it as the primary account. But not everything comes through so well, and that's why the additional backup app is great.
I also used Astro (free) to backup other apps, but I don't think it captures their settings and preferences, etc.
Back to the main issue: deleting text messages.
Handcent has an option (Menu / Delete Threads) that allows you to delete all threads. It seems to share information with the native app, so I think this might actually delete all of the text messages, period.
You might want to give that a try. If it works, I think Handcent is better anyway. If it works but you don't like Handcent, you can just use it whenever you want to put on your little French maid outfit and do some dusting.
