DJ_Steve's newest 2.2 build, the one with Stage, also includes Backup & Restore, which saves system settings, your call log, short messages, ringtones, wallpapers, web bookmarks, user dictionary, and a copy of downloaded applications (with or without their settings and data) to the Streak's SD card.
And guess what. Backup & Restore is now available in Android Market (QR code below) and clearly labeled as being "for use with Dell Streak devices only."
Since the official Froyo update will wipe your Streak and this app makes it incredibly simple to backup and restore almost everything you'd lose with a simple tap, I wouldn't be surprised to see Backup & Restore mentioned by name in the update's installation instructions.
In other words, the wait is almost over.
Thanks, Brodie!