Yes, I game on a 120" diagonal screen (16:9 aspect ratio) at 1368x768. To do this, you have to establish the graphics settings you want in the LOMAC options menu, and then manually edit the ".\Lock On\Config\graphics.cfg" file simulator info like this...
Simulation
{
resolution = {1368, 768};
bpp = 32;
fullscreen = 1;
aspect = 1.781250000;
}
Once you change the file, you can start LOMAC and the changes will be in effect. Note, if you go into options and change any graphics options afterward, the aspect ratio in the graphics.cfg file will get reset to 4:3 and you'll have to modify the file again.
Works like a charm for me. LOMAC is actually one of the few simulators (or games for that matter) that correctly handles user configurable aspect ratios instead of stretching your picture horizontally (having a true 3D cockpit helps). Looking at the round cockpit gauges on my widescreen, they are aspect correct :-)
Hope that helps,
-spearsd