It maybe doesn't fit the bill of simple, but it's not too dreadfully hard to get set up if you only want it to fulfill some relatively straightforward tasks like you describe.
Another great use of Chef and Puppet can be seen in Vagrant (http://vagrantup.com/). Vagrant uses VirtualBox (http://www.virtualbox.org/) to create virtual instances easily (REALLY easily) and then can automatically provision them via Chef or Puppet. Sweet stuff. I love the ability to bring up a new server with the things I want to have so quickly.
I'd really love to see a better abstraction than "idempotent wrappers for shell commands" which is what Chef and Puppet basically are.
Most applications are simple enough to run as a single process with a read-only file system and log to standard out. Surely someone could use the Heroku Procfile model a reasonable starting point and create escape hatches down to lower levels as you need them.
I don't know of any total replacements for ExtJS but something like Sproutcore may come close.
Perhaps I'll look at Sproutcore now that it's had more time to mature.
You're absolutely correct; without the people processes in place, the world's best tools aren't going to do anything for you. I'll ponder over that for the next blog post.
Involves some of the same folks who put on the excellent Erlang Camp I attended last year, on the basis of that experience, I'd expect this to be a good value.