Wimberley has a system of flash bracket components that are modular, versatile and easily stowed in a small space when not in use. Known as the Shape-Shifter Modular Flash Bracket System, the components connect without tools. None of the combinations slip, twist or creep-even during intense action. They're integrated with the venerable Arca-Swiss type quick release system, now dominant as the industry standard for macro and telephoto shooting.
Module 3 is a 90° arm with a flash shoe groove on top that also has a 1/4"-20 threaded screw.
Most of the various off-camera TTL adapters fit perfectly at the top (Canon Off Camera Shoe Cord 2, Konica-Minolta OS-1100, Olympus FL-CB05, Metz SCA 3008 A & Pentax Off Camera Shoe Adapter F); the Nikon SC-29 does require the FA-11 adapter plate.
If you're using a non-TTL application, a great rigid solution is to install Wein's HSH adapter on top of the Module 3, and then install your flash atop the Wein HSH.