I'm not sure if you did this already, but you need to increase the default on the service (as well as the client).

<bindings>
<wsHttpBinding>
<binding name="wsHttpBindingConfig" maxReceivedMessageSize ="50000000" maxBufferPoolSize="50000000" >
<readerQuotas maxArrayLength="50000000" />
</binding>
</wsHttpBinding>
</bindings>