From BlackRapid:
TRIPOD PLATES 50/70
Replace an existing arca-compatible plate with the Tripod Plate 50 or 70. This product allows you to switch from your tripod to your R-strap effortlessly, without having to unscrew the plate. Comes with our FastenR Tripod screw and fits all 1/4-20 sockets. It is available in two sizes 50 and 70mm.
Technical Specifications
Plate:
FastenR Tripod (FR-T1):
LOCKING BERT EXTENDER
BlackRapid’s Locking Bert extender is a great solution to lengthen your R-Strap. This option lets you add an extra 15 inches (38cm) on your sling to ensure the best fit. Comes in a locking version and a Non-locking (original) version for Curves and Doubles without the locking buckle on the back.
Technical Specifications
B&H has the BlackRapid Arca-Style Tripod Plates and Locking Buckle Bert Camera Strap Extension available for preorder.
If you already have an Arca-style L-bracket on your camera, you can use this method to make it compatible with a BlackRapid strap. [Sean]