While you can see I record my BMI, I take it with a pinch of salt, as it really doesn't work for me (I keep it because I like being able to say I am no longer obese :P). Actually, at my goal weight of 77 (169.5 pounds), my BMI is either 25 or 24.9, and I can't go under 75 or 76 kilos (165-167 pounds) at the most, because I look pretty bony
My dad has the exact same problem. He was 6'2" in his youth (I think he has lost an inch due to weight), and around the time he started going out with my mom, he got on a diet. He got to his supposed "ideal weight" of 87 kilos (191 pounds)...and he was fainting all the time (and by the diet he did, it wasnt' that he was not eating enough).
I have always had a big frame, as well as being very tall; as a kid, I was always bigger and taller than even the biggest parameters for my age. As an adult, I am 5'10'', with big feet and big hands (my hands are only slightly smaller than my 6'1", big framed dad, and my 6'1" boyfriend with pianist hands). When I was 10, as I was clearly overweight, mom took me to a nutritionist, who used BMI to set a goal...even when I was already thin (as can be seen on pics of me at the time), she kept on insisting that I lost more weight, as my BMI index was still high. Well, as a result, I was VERY thin and actually not looking that nice. I found pictures of our 6th year end of year trip, and my arms and legs look like sticks
Many years after this (I was around 19), I went to the nutritionist again, and I got the same woman. Again, she measured my wrist to get my BMI, and she said I was a medium frame (when I told that to my parents, they laughed :P), and that meant that I had to reach 66 kilos (145 pounds). Of course, I ended up quitting that diet because everybody home believed it was unhealthy. Btw, it turned out that my wrist is just pretty tiny for my body frame (last time I measured it, it was 17 cms, and 17,5 is the minimum for big frame)...probably the only small joint I have in all my body!
I should mention that BMI is pretty accurate for my mom and sister, who are medium frames.
So, at least from my experience, if you are big framed, you should take the BMI with a pinch of salt.