In comments to the Science of Sports blog post on Chris Solinsky's remarkable sub-27 minute 10 km time, data on the height and mass of those who've managed to break that barrier were listed. It's interesting to see how the numbers scale:
While constant BMI certainly describes the upper bound of these data, at the lower margin, the trend is closer to a constant ratio of mass to height. It was proposed a factor may be the ability to dissipate heat, which becomes more difficult for larger runners than smaller runners at a fixed BMI.
For fun, I also plotted my numbers, and while I'll never run close to a 27 minute 10 km (40 minutes would make me happy), my dimensions certainly fit in nicely with this super-elite crowd: