PROBLEM SOLVED. Please Delete, Sorry.
My solution if your still having trouble with a malfunctioning text vibrate is.
1. download Handcent sms
2. turn on every vibrate function on your phone possible.
3. leave your stock texting app notifications on.
4. give it a few tests text yourself. both notification icons should vibrate.
5. if so. turn off your phone for 15 seconds . and turn it back on.
6. send yourself another text message.
7.if both notification icons vibrate again. uninstall Handcent.
8. your stock texting vibrate function should be restored.
It has worked for me on my DROID 2. I hope it works for others! I was almost close to buying a different phone.
reason it worked is because hancent has a function to override your phones vibrate permissions.
hope it works for others! give it a shot!