I flipped two on their side and mounted them on my scout trailer? Got them from harbor freight. They have one their that has a zero clearance lid?! It will open to the front, unless you bought 2 put them is at an angle \ /
Those are pretty much custom. I'm having one made for my custom off-road teardrop. One side will have a 75L fridge/freezer on a slide, the other side battery and electronics. Cost to me via a welding friend will be about $1000. cdn excluding the slides.
We'd gladly build you one, even put a custom designed rack on it for ya, but being on the other coast is tough for shipping. Any decent fabrication shop should be able to make one, but it won't be cheap.
Browse our series of truck toolboxes: Truck Underbody Tool Box, Side Mount Truck Tool Box, Trailer Tongue Box, and many others. Custom Truck Toolbox Series. Fabricated by RC Industries, Elkhart Indiana (574) 295-6641