Alright, I'm going to give Pioneer another shot due to some tests I did this weekend. I used my 18v LED flashlight to simulate the sun shinning on the screen. I tested out a kenwood DDX470 and it appeared to be slightly more visible, but still not great. There are no other brands I'd want to try.
I also tried out the Sony single din HU and its not going to work for me. I'm spoiled and can't go back to a single din. Using the phone and going through ipod and usb are just FAR TOO difficult with a single din.
That said, I'm still getting rid of my x5500. I'll be replacing it with an x8500 for a couple non-related reasons. One related reason is the removable screen. Perhaps I can place it somewhere cool in the car while the car is parked. I'll also be buying one of the double din covers to act as a theft deterrent, but I also plan on lining the inside with some insulation to help keep the radio face cool (instead of taking the face off).
I also bought a Parrot Asteroid, but I'm not even going to open the box because I know I'll be frustrated with it. Part of the reason I bought the X8500 is that I'll give ARL another shot and if it doesn't work out I still have everything else I need in a nice HU (versus the bare bones SPH-DA100). Its $140 premium over the X5500 which I can handle. I'm sure I'll find something to do with that HDMI input. I'm thinking ARL didn't work good because of my phone. Once I get a Samsung, I'll probably be good.