[collin]

straight out of the shot?

I'd start out with Drupal if you are comfortable with it; you should be able to bang out an accurate prototype in a couple of days. Then you'll be in a place to find out what you dont like about it.

So what if your app would keel under load? Do the detailed deployment work when you know you've got something worth deploying.

I wouldn't even be surprised if bits of Drupal could be tuned to perform very well under duress. No idea what sort of license issues that could bring up.