The following are Ruby object representations that can be serialized with .to_json.  We can also filter this structure with .as_json methods on the components of this structure before handing it off to serialization in .to_json.

 Proposal #1

{:card =>   # I think {:cards => [ {:name=>"Home" ...},{} ...]} is what we want, although we can consider that different view parameters 
            # could select either/both kinds of root node. If :card represents a codename, we could put the cardname of that card as the
            # element name to give wagneer control ...
 { :attributes =>
    {:name =>"Home",
     :cardId =>80,    # optional, but when present is an unchangable Id of a real card
     :type_id =>3,   # :type would be the typename, I think, and we can have :typecode optionally as well
     :class=> ..., :style =>nil, :home_view =>nil, :item =>nil, :base =>nil  # These Html orientled style attributes may be supplied (when non-nill,
         # of course) as needed to  populate these attributes in the DOM, but most of the time we will let the Html rendering populate this style information 
          },
   :result =>[  #  :result is probably the wrong name, these are the child nodes, the woudl be inside the <card> </card> tags in Xml, and 
                #  in Json this is often called :children.  I think :contents would make the most sense for cards, but maybe that is a
                #  codename and changable by rename?
      "<h1>Welcome to Wagn!</h1>\n<p>&nbsp;</p>\n<p>",
      {:cardlink =>{   # view controls on the nested inclusions would say whether this is rendered like this as a nested data object represeting the
                       # link or something rendered at a link to string
          :class =>"known-card",
          :url =>"/Config"
          :text =>"Start configuring"
      }},
      " or learn more:</p>\n<ul>\n<li>",
      {:link =>{
          :class =>"external-link",
          :url =>"http://wagn.org/wagn/configuration",
          :text =>"Configuration"
      }},
      "</li>\n<li>",
      {:link =>{
          :class =>"external-link",
         :url =>"http://wagn.org/wagn/Documentation",
          :text =>"Other Documentation"
      }},
      "</li>\n<li>",
    {:link =>{
          :class =>"external-link",
          :url =>"http://wagn.org/wagn/Support",
          :text =>"Support"
      }},
      "</li>\n</ul>\n<div><em>Double-click content to edit.</em></div>\n<p>&nbsp;</p>"
   ]
 }
}

Proposal #2

{ 
  :card => {
    :name    => 'whatever',
    :type    => 'Basic',
    :content => (raw content), # for export
    :parsed_content=> [
       'I include:', {
           # should this be in :card?
           :name => 'whatever else',
           :type => 'Phrase'
        }, '!'
      ]
    } 
    # other card metadata
  }
  # request metadata, etc.
}

Proposal #3 (actually generated in wagn)