I just don't see what the big deal is about the HDD cage. The slots are exactly where the hard drives aren't, so even turned 90 degrees like in the above pic, as soon as you put drives in the cage, you're going to be blocking the airflow just as much anyway. If you need more airflow for your vid card, that's what the fan slot in the bottom in front of the psu is for (and in the side panel). To me, it seems like a heck of a lot of work for just a little bit more airflow, plus, the HDD cage is one of the reasons I like this case so much; it's just easier to get drives in and out with it facing the side like that...just my $.02
I'm thinkin' about removing the bottom part ,below the case fan,i mean just the "mash" or the gril holes.
http://img132.imageshack.us/img132/4421/cm690.jpg