During the time period of his famous letter to the "Baptists" the House of Representatives was holding church services, which he attended. He actually attended a service two days after the writing of his famous letter in which everyone tries to hang on to one or two sentences. He didn't address State sponsored religion, but was referring to Federal laws that restricted or promoted religion. Funding of organizations wasn't a topic. Madison was against the same things, noting that several denominations of Christianity were attempting to have laws written favoring their denomination over others, thereby, infringing on people's conscience. There is absolutely nothing I disagree with in his or Jefferson's writings. Problem is, y'all want to add to their writings rather than let them speak for themselves. The early practices of the Federal government, prayers in the House, the posting of Scripture in the Halls of Justice, etc, a long list of religious promotions in every aspect of our lives, didn't involve writing laws or promoting one denomination over another, but promoted the free exercise of one's religious convictions without government interference. That all this God stuff was surrounding every aspect of our government is proof enough that they didn't call for the wall in the way you describe it, but one a bit different.