HTC features a nice built-in SMS backup / restore feature on its phones. From within the SMS app you can export messages to a .hbk file, and then you can import that file (on the same device or another) to restore. It's all explained in this support page. Simple, right? Well, nope! That page neglects a key step without which restores will fail because the device will not see any available backup sets. For restore to work you must create a top level folder named "sms_backup" and save the .hbk file there and then attempt the restore, as that is the only folder the restore utility looks in.
Posting this one so that I have it for future use.