You know, I'm doing something similar myself. If you  bug me enough, I might just zip up and post my XML-to-object graph code, though I make to guarantees about its security, performance, or bugs.

Given something like
   <?using System.Windows.Forms?>
      <Button Text="Click Me">
         <Size>75, 20</Size>
         <Location>8, 8</Location>

It will give you what you expect. Just pass in an XmlNode and you get an object back.

To do the scripting bit, you can probably just make a set of scripting objects and have all the text parsing done there.