When I first bought my mountain bike back in May I didn't have any sort of bike rack, so I just went about folding the rear seats down and laying the bike in the rear of the FJ. This wasn't really ideal since the bike takes up quite a bit of space laying down, and could be a (very) dangerous projectile during an accident.
Fast forward to now, I have a solution that allows me to store the bike inside the FJ for MUCH greater security than an external rack, and keeps it out of the weather. Comprised in this solution is a Thule quick-release fork mount for attaching to the bed of a pickup, and some bungee cords from the local auto parts store.
I screwed the Thule clamp into the plastic on the rear side of the back seat, which by itself is NOT sturdy at all, but keeps the front of the bike down. The green bungee over the top of the rear tire provides most of the side-to-side stability, and holds down the rear of the bike. I also use a shorter bungee to hold the front tire against the subwoofer, and other various bungees for accessories. Since the bike is mounted diagonally, use of the 40% width back seat is retained. I usually push the non-drive side upper chainstay against the back of that seat for additional stability.
Cost: less than $40
