I felt there was a pretty good selection when it came to sidewall heights for 17" tires. Like I said before, I have a set of 255/60-17 on the rear, which are 29" tall. With a 3.91 I am right around 3000 RPM at 70 mph. This size tire is actually classified as a light truck/SUV, if that helps with the search. I bought these used for $35 each, and they are about due for replacement. My next set I am looking at 255/55-17, which will be about a half inch shorter. I can only find 2 in this size at Tire Rack, but I figure it will be the last set I buy for this car, so price is not much of a concern.
As far as the rear end sitting low, that's pretty common for the stock leaf springs. If you ever feel like raising it up a bit, you can get a set of springs through Espo, etc, that will raise it up a good inch or two.
The main reason I am kind of going on about this is because the first set of 17" tires I bought were 235/45-17 front and 255/45-17 rear, and I was not happy with how small they looked. I was dumb and allowed the tire shop guy to talk me into these because it was the largest size their computer said would fit. After after doing my research after buying them, I realized I pissed away $600, but still went with the larger tires. My fronts are 235/55-17.
The first picture is the first set of smaller tires, and the second pic is the current setup. It might not be quite as obvious in the pictures, but it was definitely a huge visual impact when I changed them.