Cool! A great example. I'd suggest posting about this over in the PureMVC PHP forum as well.
In my quick look at the code, I'd make 2 minor suggestions:
Read this post about not reaching into the PureMVC apparatus from the index.php:http://forums.puremvc.org/index.php?topic=1234.msg5721#msg5721
And reorganize the classes into model, view and controller folders rather than having them all in one big folder. (i.e instead of iwbase/classes/*, have iwbase/model/*, iwbase/controller/*, iwbase/view/*).
This will make it more recognizable to others since it is the standard PureMVC project layout. And it will make it more maintainable. As the number of classes grows (and even now) you have to look and look to find the file you want in this long folder listing, and the classes arent grouped by type, they're alphabetical.