Ratz, if you got a 55 gallon tank stand that can house 2 tanks you may be better off getting a 40 long. A 40 long will fit nicely under the 55 with room to get into it. A 40 breeder is wider than a 55, so may eventually cause the tank to crack as it will not be properly supported. Just a thought

40 longs have the same foot print as a 55, 4 feet long, 12 inches wide, they are just shorter.
40 breeders are 3 feet long and 18 inches wide. So it will overhang front to back, which can eventually cause a stress fracture to form from the pressure of the water and not being properly supported.