The best alternative is carrying a .45 1911 in an IWB holster and a 9mm Hi-Power with a 30 round clip in the briefcase in case you need more firepower and a .40 SIG 229 in an ankle holster as a backup.
The best of all worlds, plus include 50 rounds of each ammo in your pants pockets. This way you will be properly armed and also increase your physical fitness carrying around all the extra weight.