extjs 4 & codeigniter

[eluser]mikerh[/eluser]
sencha cmd is used to generate the initial Ext base app, themes, etc. It also is used to do the final build of your app which concatenates just the parts of extjs you need, all of your app MVC classes, and uses YUI compressor to make a single small file. This file and your CSS file is then all you need to put on your server (along with your codeigniter files).

http://docs.sencha.com/ext-js/4-1/#!/guide/command

I have been developing with extjs and codeigniter for a while now and have a pretty good structure/routine in place if you are interested.