You might get away with "kicking the can down the road" by spray-painting the existing red and amber lenses black.
Here are a few options that came to mind (never used 'em myself, nor even worked with this vendor, and I don't even know exactly how big the existing cut-outs in your sheet metal will be but these might fit or be bigger):
etrailer doesn't actually say what lamp is in the former but I found on the Optronics web site that it takes their A1156 replacement lamp. If it's the same as any other automotive 1156 then it's 27 watts at 12.8v. Not exactly what I'd call a "spot light" but maybe enough for backing in at night..? The latter, obviously, will provide plenty of light!
Are you looking to place those on the front, rear, or both? You might want to check your state's laws regarding lighting; these might qualify as "off-road" lights which in some places are supposed to have opaque covers installed when the vehicle is on-road.
Specifically for backing in at night, and not for general illumination, you might look at a 50w or 100w 4-inch "tractor light" type thing or a fog light hung from the bumper. That'll put a lot more light on the ground, but if you're worried about backing into overhead obstacles like tree limbs or roof overhangs, maybe it's not so helpful.
