A direct (but not very elegant) way could be:
ClearAll["Global`*"]
SetDirectory[NotebookDirectory[]];
input1 = Import["first.txt", "Data"];
input2 = Import["second.txt", "Data"];
result = Join[input1, input2, 2];
Export["result.txt",
StringReplace[
ToString[result], {"}, {" -> "\n", ", " -> "\t", "{{" -> "",
"}}" -> ""}]];
But I have to confess that this is not solving your primary question: This way the entire input files have to be red in first.
Henrik
