Glad you got it working - FYI we make use of WCF in Evoq Enterprise (to provide content synchronisation between 2 sites i.e. staging and production), and in that case we add some simple settings in web.config e.g.

  <system.serviceModel>

    <behaviors>

      <endpointBehaviors>

        <behavior name="ContentService">

          <dataContractSerializer maxItemsInObjectGraph="10000000" />

        </behavior>

      </endpointBehaviors>

    </behaviors>

    <client>

      <endpoint binding="customBinding" bindingConfiguration="BinaryBinding" contract="DotNetNuke.Enterprise.ContentStaging.Contracts.IContentService" name="ContentStagingEndpoint" behaviorConfiguration="ContentService" />

    </client>

    <bindings>

      <customBinding>

        <binding name="BinaryBinding">

          <binaryMessageEncoding />

          <httpTransport transferMode="Streamed" maxReceivedMessageSize="104857600" />

        </binding>

      </customBinding>

    </bindings>

    <serviceHostingEnvironment multipleSiteBindingsEnabled="true" />

  </system.serviceModel>

but we add a fuller definition in the web.config of the desktopmodules folder where the WCF code resides (this helps ensure we don't pollute the entire application but only requests to the .svc 's in that folder. Note: we transfer a token with each request to confirm the handshake between sites (i.e. both sites agree to the trust), so our setup is likely a little different to yours, but I thought you might appreciate a look anyway.

<?xml version="1.0"?>

<configuration>

  <system.webServer>

    <security>

      <requestFiltering>

        <requestLimits maxAllowedContentLength="104857600"/>

      </requestFiltering>

    </security>

  </system.webServer>

  <system.web>

    <httpRuntime maxRequestLength="102400"/>

    <compilation targetFramework="4.0"/>

    <pages controlRenderingCompatibilityVersion="3.5" clientIDMode="AutoID"/>

  </system.web>

  <system.serviceModel>

    <behaviors>

      <serviceBehaviors>

        <behavior name="ContentService">

          <serviceMetadata httpGetEnabled="true"/>

          <serviceDebug includeExceptionDetailInFaults="true"/>

          <!--Increase this value if you have modules that contain large number of items (lists of items)-->

          <dataContractSerializer maxItemsInObjectGraph="10000000"/>

        </behavior>

      </serviceBehaviors>

    </behaviors>

    <services>

      <service behaviorConfiguration="ContentService" name="DotNetNuke.Enterprise.ContentStaging.ContentService">

        <endpoint address="" binding="customBinding" bindingConfiguration="BinaryBinding" contract="DotNetNuke.Enterprise.ContentStaging.Contracts.IContentService">

          <identity>

            <dns value="localhost"/>

          </identity>

        </endpoint>

        <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/>

      </service>

    </services>

    <bindings>

      <customBinding>

        <binding name="BinaryBinding">

          <binaryMessageEncoding>

            <!--Increase this value if you have modules that contain large amount of content-->

            <readerQuotas maxStringContentLength="8388608"/>

          </binaryMessageEncoding>

          <httpTransport transferMode="StreamedRequest" maxReceivedMessageSize="104857600"/>

        </binding>

      </customBinding>

    </bindings>

  </system.serviceModel>

</configuration>