The answer is a resounding yes! So after our week long road trip over July 4th weekend, spanning over 1,774 miles and using only 2.75 tanks of gas ($103 total spent in gas), I picked up our new Samsung 51" plasma 1080p HDTV, new in box, from Best Buy and loaded it into the cargo with absolutely no problem. More on the road trip in a separate entry.
There was still enough room left over for additional accessories. I also picked up a Samsung 5.1 3D Blu-Ray home theater system and sat it on the passenger seat. If I moved the front seats forward a bit, loading a 60" HDTV new in box shouldn't be a problem at all.