Review on Enchanted Home Pet Orthopedic Sturdy Backseat Extender with Storage: Black, Large (51 - 100 lbs) - Ultimate Comfort and Convenience by Melissa Marie

This really worked for me. I have a Subaru Outback with a hammock in the back seat for my German Shepherd. I chose this because on long trips I hated losing storage space behind the passenger seat with the foam block seat extender. It now contains all the dog supplies I need and a few essentials I like to have on hand. One caveat is that I'm a tall guy and with my driver's seat in a comfortable position, it doesn't fit behind my seat. My wife is smaller and doesn't like to sit as far back as possible. She likes it a bit forward rather than all the way back, so this unit fits perfectly behind her seat.