Quick Edit Signature and Change Theme

[HARP]

Hello, I would like to add a page specifically for quickly changing your signature.

My first question is, how do I make a custom page which allows solely signature change?
I would like it so that it has the Signature Edit box at the top, preferably with the BBCode buttons available.
I would also like the current signature to be visible at the bottom of the Edit box while the Preview is above.

I am not too sure how to go about this. I have attempted this but cannot seem to understand how to get the values to appear. Here is my code so far. The Signature edit part is not specific cause I could not seem to find the specific code for that, but can't even seem to get the generic profile edit to display. Nor the current signature.

$[zone_1]
<div class="js-edit personal-edit           $[edit_area.display_personal]">
$[edit_personal]
</div>
$[zone_2]
<table>
<tr>
           <td id="center-column">
{if $[user.signature]}
<div class="content-box center-col">
Signature <hr />
$[user.signature]
</div>
{/if}
           </td>
       </tr>
</table>
Do I have to make a widget for the custom page, or is this more of a custom plugin feature, or am i just flat out using the wrong code?

Thank you for your time.

[Chris]

Although the personal page now has its own XHR endpoint I think it is still tied to a referral url so you couldn't for example set user-A's personal text or signature while on user-B's edit profile or on some random custom page. Basically you can try to recreate the look on a custom page but the mechanism behind what gets sent and accepted on the other end is not under our control, the server expects a json call of that type to be coming from that page and that page only

Note: I tested this back when things were first converted from form submit to XHR on the profile settings page so may have changed.