Create rows from combination of other rows

You can accomplish this via a custom function created in Google Apps Script. To achieve this, follow these steps:

• In your spreadsheet, select Tools > Script editor to open a script bound to your file.
• Copy this function in the script editor, and save the project:

function REPEAT(table1, table2) {
  var output = [];
  output.push([]);
  for (var i = 0; i < table1[0].length; i++) {
    output[0].push(table1[0][i]);
  }    
  for (var i = 0; i < table2[0].length; i++) {
    output[0].push(table2[0][i]);
  } 
  for (var i = 1; i < table2.length; i++) {
    for (var j = 1; j < table1.length; j++) {
      output.push([]);
      for (var k = 0; k < table1[j].length; k++) {
        output[output.length - 1].push(table1[j][k]);
      }    
      for (var k = 0; k < table2[i].length; k++) {
        output[output.length - 1].push(table2[i][k]);
      }       
    }
  }
  return output;
}

• Now, if you go back to your spreadsheet, you can use this function just as you would do with any other function. You just have to provide the appropriate table ranges as parameters, as you can see here:

I hope this is of any help.