Mounting a PCB with no holes
Digikey under "board supports" in link below and then in parametric search under "holding type" choose "edge" and "corner". There's about 10 or so suitable parts.

http://www.digikey.com/products/en/hardware-fasteners-accessories/board-supports/578

Also, if you dont mind ugly, just use long screws protruding up from your base plate, a nut to hold that screw rigidly, a second nut at the height of the bottom of board, the edge of the board pushed against the screw and then a third nut to hold the PC board down. Loctite to keep nuts from loosening. Ugly but will work.