Many "suits" round here carry those day-planner thingys and that might house a small folder nicely. Also if you have a soft-sided belt wear for your cell phone or pda you could stuff a folder in that holster without causing much of a noticeable bulge if you use something like the KISS. With some of the longer cellphone / PDA holsters you could get a fixed blade like the ArcLite cuda into the holster without it being noticed. The trick with this is the thickness not the length of the knife.