Ive done some investigating and have finally come across a mob that makes an upgraded CV/driveshaft for the FJ cruiser........
https://rcvperformance.com/store/catalog/product_info.php?products_id=47&osCsid=ae949032e8cb461586b38411e44108b9
RCV Performance has completely redesigned the inboard joint replacing the fragile factory set-up. The RCV Performance Ultimate FJ inboard joint allows for more articulation on lifted FJ's. The billet aerospace alloy center bar is heat treated for maximum strength and torsional flexing. The OEM outboard is beefed up with chromoly internals. All sales are done on an exchange basis. An OEM axle with a usable outboard joint must be sent in for this upgrade. The outboard joint itself is pretty stout and to keep the cost down it is rebuilt with upgrades internal components by one of our factory trained technicians. All RCV components guaranteed against breakage and 100% customer satisfaction guaranteed or your money back. **PRICE IS FOR ONE SIDE ONLY!**
The price is $585 US per side, but they do have a guarantee against breakage so they must have some faith in their product. And yes, I do understand that by beefing up the driveshaft you putting extra stress on other components such as the diff centre itself......
The FJ driveshaft thou will not be a bolt in application for the hilux, as we found out in the drvietrain bible I beleive it was, the outer shaft has a different spline count due to the Prado/FJ Hub being slightly different but everything else is the same, so there no reason if you were serious about upgrading that they couldnt make a set for you to suit.....
Steep price...good product...you pay for what you get.....