What is the maximum size that maxReceivedMessageSize can be set to for a NetNamedPipeBinding?

Nope, the limit is Int64.MaxValue1 which is: 9223372036854775807


MaxMessageReceivedSize in basicHttpBinding appears to be an int32 - setting it over the max value of an int32 results in:

This factory buffers messages, so the message sizes must be in the range of an integer value. Parameter name: bindingElement.MaxReceivedMessageSize


MaxReceivedMessageSize and MaxBufferSize must same value and MaxBufferSize is Int32.