I have a fairly "inexpensive" case (that came with a Skyhawk PS) that did not have much in the way of options and space for extra fans. I replace the PS with a dual fan Enermax. Then, I was able to mount 2 60mm fans, one one on top of the other, along the back wall about "cpu high", for additional exhaust. There was not enough room for an 80mm fan but the two 60's (low speed) work just fine. I also installed an 80mm panaflo on the bottom of my case for additional intake because the front intake fan had horribly blocked airflow. I guess my point is that, "if there's a will, there's a way." You can always get creative.
BTW, my "office" here at home in N. CAL is not air conditioned and reaches 85-90 at times also. My system maxes out at around 48-50C during those hot times. Not what I want, but the best I can do; it still is stable and keeps on chugging 24/7. Get out the dremel and give it a shot.