Arnold talked about his thighs being 28" at their best. He, of course, wasn't known for great thighs, but they did look decent in 73-74 or so. And, he was just over 6'. It's all about the shape. I've got a buddy who is 6'1" or so and has 26" thighs that look great. He's not a huge guy, 220 or so, but he has complete development down to the knee and good sweep. That makes a big difference. Anyhow, my thighs are 26" and look like shit- I'm 6'2" and they are a major weakpoint for me, thighs and back thickness are what I'm working hard on. Good luck!
Jacob