My daughter deleted all my iPhone's texts, many of which contained important information, and it had been a while since I last synched. I know I can restore texts from before the previous sync, but I presume I'm out of luck on any texts since then?

Also, how would one archive texts on a Mac, so they could be safely deleted from the iPhone but still findable in storage somewhere?

I think iPhones should have a "trash" folder like Macs do to give one more layer of protection against unwanted deletions.