Yes, a single Frontosa will do just fine.
Since the tankmates have to be big as well, you're a bit limited to how much you can put in the tank. A big catfish or loach, a big algae eater - this will pretty much fill up the tank.
In your position I would be inclined try a small shoal of silver dollars with him. While they are not from the same biotope, they'd coexist indifferently with each other. Now I'm sure you'll hear all about how the water is different, blah blah blah, but frankly, these fish will both do well in neutral-ish water while giving you something to fill the tank with.