you could add a "camera_adapt_aspect();" function

I simply create 2 more mode for 1280x800 (16:10) and 1280x720 (16:9).
Code:

---

		switch(res)
		{
			case 13:
				video_set(1280, 800, 0, 1);
				break;
			case 14:
				video_set(1280, 720, 0, 1);
				break;
			default:
				if (res < 6 || res > 12)
				{
					res = 6;
				}
				video_switch(res,0,1);
		}
		if (integer(sys_metrics(0)/sys_metrics(1)*100) > 133)
		{
			camera.aspect = (sys_metrics(0)/sys_metrics(1))/(4/3);
		}

---

I haven't test it on wide screen yet.

I tested this code and the aspection width was to small and all objects looked bad. This is a Problem with to low values.
Here is the code that works better with 16:10 and works also with window mode not only in fullscreen!

video_set(1680,1050,0,1);
wait(1);
camera.aspect = (screen_size.x/4) / (screen_size.y/3);

The wait(1) is to ensure that the vector screen_size is set to the new width and height of the 3D window/screen.

OK I found what's wrong, change the line to this
Code:

---

camera.aspect = (sys_metrics(0)/4)/integer((sys_metrics(1)/3));

---

Now you can add any mode you want and you will got correct aspect.