Silva Content Layout proposal

Greetings Devs!

Bethel University is the middle of a site redesign.  We've partnered with a 
leading US design firm that specialized in higher-ed websites.  In addition to 
the general site template (what is normally configured using the 
content_layout macro or a SilvaLayout layout), we are getting about 12  page 
layouts for specific types of web pages.

Silva is currently not very capable of complex page layouts. Between the 
header and footer and other required components of a page (e.g. nav menu, 
breadcrumb, etc), anything beyond one column (i.e. a silva document) is 
prohibitively difficult for our authors to create.  One of our 12 layouts is a 
"one column" layout.

I've been thinking about this problem for a long time, and now it's time to 
get to work.  I've drafted a proposal on how I think content layouts should be 
handled, and it's quite a dramatic shift on how the Silva editor functions.  
We've looked at a number of leading open source CMS's and have found them 
lacking.  Commercial CMS's (like cascade server, sitecore, etc) do support 
this in some fashion.  I've heard rumors that Plone is heading this direction 
as well.   This is a pivotal moment in Silva's development.

This proposal is a launchpad blueprint, here: 
https://blueprints.launchpad.net/silva/+spec/silva-content-layout

I'd like to generate some discussion on this, and hopefully be able to 
collaborate on this with other Silva institutions and Infrae.   
Ultimately I want this to end up in Silva's core, becoming part of the 
standard Silva CMS, so that everyone can enjoy it.

The full specification is linked to from this blog post:
http://www.bethel.edu/web-services/blog/posts/2009/content-layout
I know other institutions are interested in this, so please tell me what you 
think.

Cheers,
Andy