Jawinn,
Have you looked at the 3.5.4 modifications? Abe1 made a brilliant form hack which does exactly what you want it to do. It's called FORMS HACK i think. You just install the xml file, the user goes to
http://xxxx.newthread.php?do=form and then there's your custom form.
You can have it post the response to a forum, e-mail a user, or PM somebody.
Pretty cool.