I have looked far and wide for a belt without a buckle that hurts me when I bend over or go through a window. Found it from Duluth Trading. It's modeled after gunslingers' belts. Also, go to Duluth for long tee shirts (to prevent "plumber's butt") triple seamed, gussetted jeans (that don't pinch your delicate parts when you bend over) and hats for big heads! Their new pants even have spandex in them for making it easier to climb out of windows. Clicking on belt will take you to Duluth.
And here's a brand new one that flexes and has a gut-friendly buckle. I wear with all my non-work pants. Click image for link.