Yes! After more than two years of possessing the Droid2, I finally became frustrated enough to determine how to to turn on vibrate mode for incoming text messages. By simply googling "Droid2 wont vibrate for text messages" I selected the first link and wallah:
1) Go to your text message inbox
2) Select the menu key ("the four squares" on the bottom left of the screen (or middle-right, depending on perspective)
3) Hit the third option, "Messaging Settings"
4) Scroll to the very last option, which is under "Notification Settings", and check on "Vibrate (Also vibrate when notified)"
... I should have done this 2 years ago.