Split ExtJS for incremental (on demand) download

I had ear开发者_Go百科lier asked whether I can remove un-utilized JavaScript code from ExtJS library. JSBuilder was the answer.

What about being able to download widgets on-demand? I ask this because I have discovered this from the of markup generated by Coolite (ASP.Net framework that wraps ExtJS). So do I have to go through a meticulous process of splitting the library myself or is there a better way? BTW I'd like to avoid using Coolite.

Check out http://www.extjs.com/forum/showthread.php?p=225658#post225658