Slee Offroad makes them for the FJ80 and FJ100 series but does not list one for the FJC. You can try contacting them for a custom panhard link for the FJC. Jason DeMello may be interested in making a custom panhard link as well.
They make them for the front axles of YJ's, I would think you could find one for a Yota 8 inch, but when I had my YJ, I had troubles finding one for the rear.
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Sun Fusion FJC 4x4, AT
OE Rock Rails, OE Hitch, OE Rack
3" Skyjacker lift
TRD Wheels
285/75/16 Cepek FC-II
KC SLim Lights
Tuffy light bar with 2 Dick Cepek C-1000's
Viair Portable compressor
All-Pro Ultimate Links
If your goal is to re-center the rear axle after lifting, then you should probably look at some math. A 3" lift kit, which actually levels the car a bit and lifts the frame off of the axle by about 2", pushes the axle toward the passenger side by about 0.04". A 6" lift kit, which raises the frame about 5" in the rear offsets the axle about a quarter inch to the right if the stock panhard bar and mounts are used. Good luck measuring that subtle a misalignment.
Ideally, the panhard joints need to pivot on an axis right where the axle hits the bump stop. If you increase the length appreciably, then you'll offset the axle to the driver's side when the wheel is compressed up into the driver's side wheel well. If for some reason you shortened the bar (and moved the mounts inward) then when the suspension articulated it would draw the wheel inward into the wheel well and could possibly rub. If you lengthen the mounts and drop the bump stops, then you can recreate stock geometry with a significant lift, but it would be useless in terms of increasing suspension articulation.
There are some inherent design limitations in this system.