Most residential meters max out at or under ~450,000 BTU/hr. Some max out as low as ~250 or ~300K. Somewhere on the nameplate there is usually a cubic feet per hour at 1/2" water column pressure difference. Multiply the CFH @ 1/2" W.C. number by 1.02 to convert to KBTU/hr. Sometimes the CFH number is embedded in the model name.
To go bigger than that would require a different meter, but I'd be surprised if there isn't sufficient capacity on the drop line to the main or the main itself to handle substantially more. They generally size the capacity of the mains in developments for normal residential peaks, and they may deny you a bigger meter & regulator even if the grid capacity can currently handle it rather than set a precedent that could potentially overwhelm the capacity.
Why are you maxed out- do you have a pool heater or something on it? Or is it a <300 CFH meter?