There are three contenders I have ridden and I'll weigh in on them here. Those are the BMW R1200RT, the Honda ST1300, the Triumph Sprint. Generally when you're looking for the sport touring bikes, the choice comes down to wear in the sport vs. touring compromise the manufacturer has made. The feature differences largely center around creature comforts, riding stance, and convenience items. I'll start by covering the bikes in the order of sporty to touring, and make comments on height for each of them.
The first bike is the Triumph Sprint. This is a bike that is closest to a sport bike out of all of them. Unlike the BMW and the Honda, it does not have amenities like an adjustable windshield. In favor of a more sport like stance, the bike keeps your legs tucked and your body leaned more forward than the others. As far as the computer goes it has the standard options you would expect. The side bags are large, but not large enough that they can actually hold a full size helmet. The bike does wonderfully cornering, and even though it is the most anemic engine of the three, it does a reasonable job of handling. I have to admit I don't have a whole lot of experience riding this aside from exchanging bikes with a friend of mine. Since it is a sport bike seating position for tall riders is more of the tucked in variety you find with sport bikes. A tall person will not have a problem with it, but after any amount of time the ergonomics will start causing problems. According to the same friend, after about 80 miles it's time to get off the bike and stretch.
Second in order of sportiness is the Honda ST1300A. This is the bike I own and have the most experience with. The seat on the 13000 comes with and adjustable setting. I've only ever ridden this bike with the stock seat adjustment in the high position. It does a decent job this way, and helps to alleviate a lot of the problems from shorter seats. While seated on it, I can place my feat flat on the ground and never feel out of control with regard to the stability of the bike. In its stock configuration, I found that my main complaint was the seat, followed by knee pain on long trips.
To fix the seat I made a couple of modifications. The first was to send the stock seat to Frank Turnier at Spencer's Moto Care. Frank does a fantastic job modifying seats. He replaces all of the foam of the stock seat, and tunes it to your ass. On the order form you specify your height, weight, inseam, and riding position and he performs his magic. At the time I got the standard modification as well as the long ride gel modifications. Where the stock seat caused excruciating pain after a few miles, Frank's modifications made the bike into an all day rider. It really is amazing what the modification does. The price is extremely reasonable at $75 for the full set of modifications. The turn around time is fast, I sent my seat out and had it back within a few days (minus shipping).
The next major modification I needed was a bit more leg room so I added a seat riser from Motorcycle Larry. This effectively eliminated any of the knee pain I was feeling. To further add to the comfort of the ride I added the highway blades, and pedal lowering kit. The blades allow you to shift your riding position and get more blood into various areas of your body by extending your legs.
The Motorcycle Larry seat risers installed, and set to the highest setting.
The BMW R1200RT is the last in my list, and furthest away from the sport side of the spectrum. While modifying my ST1300 I considered just trading it in for a BMW which includes many of the features I was looking for. Out of the showroom the BMW has a couple of advantages. First, the handling is superb. It is a much lighter bike than the Honda, and handles at least as well as the ST1300. The Sprint is best overall in this area. Second, it can be fitted with many options that make the ride more comfortable. Heated grips, a seat warmer, cruise control, built in power for heated gear, and a decent stock seat make for many creature comforts. The bike I test rode had a stereo system with iPod and auxillary in for satellite radio. The stock seat is much more comfortable than the stock seat for the ST1300 and the Sprint. The height of the seat is likewise adjustable, and felt fine for what my 45 minute test ride.
The only problem was the adjustable windshield. While the 1300 handily cleared the air around my head, alleviating the need for ear plugs, the RT did not. There's a small dip in the windshield that made it so the wind did not quite clear the top of my helmet. Some quick research shows replacement windshields that would alleviate the problem.
The R1200RT and the ST1300 are both good bikes for taller people. Given the number (and more importantly price) of modifications needed for the ST1300, it comes out to nearly even with the BMW. Accounting for maintenance, the Honda definitely is the clear winner. While I chose the ST1300 the BMW is certainly a good bike to consider.