post new thread using own code

[ub.ch]

heya
I am trying to change some ways of the works of vBulletin.
The "normal" way - as far as I know it - is to click through the forum hierarchy to find the (sub)forum you would like to post in,
then click on it, see the list of all recent posts and then click on the 'new thread' button.
Now my plan is, to do it differently: the user clicks on "new thread" (or question or whatever), get a very minimalistic (like quick reply) WYSIWYG and can enter
title, text etc.
Then, using some AJAX and JavaScript stuff (think of suggestive search) find the right forum to post the thread into and voila that's it.

Now my question is, how to best achieve this. If at all possible I would not want to duplicate newthread.php or adjust this template, but code something of my own and rely on some vBulletin API to create the form.
(the whole form and steps will still be within a vBulletin environment, so I am not sure if the mobile API would work)

Any thoughts?

Thanks!
Malte