On my old BlackBerry, all my notifications for 3 different email accounts, text messages and calls showed up in one mailbox. If nothing else, it was very convenient and i got used to it.
On my Torch, I've got all my various email accounts tied to one mailbox, but I can't figure out if I can tie in the text messages and missed call notifications into that same mail box.
You can definitely tie the SMS texts with the universal inbox. Just go to the options in the menu within the inbox. I don't think missed calls can be though, but they still show up in the pull-down menu at the top of the home screen.
Missed calls can also be put in the message box. Go to the phone screen, hit your menu key, select options. then "Call Logs and Lists". Then select All Calls, Missed Calls, or None.