Yes, it is very likely that it will work with your L brackets.
Most L-Brackets have a cut-out area around the connectors, so you still have access to the sockets. This is exactly where the Unleashed plugs in, and since it is so small, it will usually fit in that cutout area.
On Nikons Pro DSLRs, the Unleashed N1 is attached to the front of the camera (round 10 pin port) so it’s out of the L-Brackets way anyway.
If there isn’t a cutout for the cable that you need for some Nikon cases, most L-Brackets have a slot rather than a hole for the tripod mount screw that attaches it to the camera. This means you can shift the L-bracket a little bit and make space for Unleashed (or the optional USB cable).
These are the measurements of the new Unleashed:
C1, C2: 13.7 x 35.2 x 5.5 mm (10 mm with plug sleeve)
N1, N2: 13.7 x 16.0 x 5.2 mm (N2:7 mm with plug sleeve)
C1, C2: 0.54 x 1.38 x 0.21 in
N1, N2: 0.54 x 0.63 x 0.20 in