I have a specific requirement to remove all client WCF configuration (
You can separate out your WCF configuration using configSource. Instructions here:
http://weblogs.asp.net/cibrax/archive/2007/07/24/configsource-attribute-on-system-servicemodel-section.aspx
Another option is to configure your WCF services programatically.
System.ServiceModel.Configuration.ConfigurationChannelFactory
et al support reading the configuration from a System.Configuration.Configuration
instance. Which means you can put the <system.servicemodel ...
stuff in a dedicated file without referencing it from web/app.config. You could have multiple config files, one for each client.
SharePoint 2010 uses that excessively in its service application model, where each service proxy reads its settings from a dedicated .config which is not necessarily web.config or app.config and isn't even referenced from there.