3 lenses and one body? Check out FX3 Super Compact
I use the FX3 Super Compact probably the smallest bag on the market that carries the most. I put a lens standing up on each side, whatever lens is on the camera in pointing down in the center. I keep a strobe in front, LumiQuest f diffuser in the end pocket and tape recorder on the other side. The bag is small so it won't attract attention, but you can change lenses quickly, get through revolving doors easily.