I have always thought a simple "portal" solution in MS Windows would be this: With the cursor positioned over any blank area of desk top (no matter what window was active, even a doc editor), hitting the space bar opens a cmd prompt "line." Just a simple, one line window. Entering something equally simple, like "c", expands the "line" to a full cmd "window." But if you are only interested in executing .bat, .com, .exe files or utilities, a simple "line" is all you need. Perhaps another key stroke is better than simply pressing the space bar, but it should be trivially easy to bring up a command line.