Good suggestion. I've found that there is enough space inside the FAT wrench box to put a small hex driver, and still get the lid to close. Then it's just a matter of adding a few extra bits that you use frequently (T10, T15, 5/32 Allen, 3 mm Allen, etc.). Then you have a screw driver and a torque wrench, each with the correct bit.Make sure to get a Wheeler FAT Wrench. Also, get T10 and T15 Xcelite drivers. They will come in very handy.
Although the Wheeler FAT Wrench comes with nine bits, they don't include either the T10 or the 3 mm Allen bits, which are commonly found on Burris, Millet and other rings. The 3 mm Allen bit is not even sold by Wheeler, which is mystery to me.
That's why HighPowerOptics includes the T10 and 3 mm Allen bits with the Wheeler FAT Wrench (total of eleven bits).
HPO/Wheeler FAT Torque Wrench 553-556 w/ 3mm and T10 Torx bits