As a guy with a 38" insearm (96.5 cm) I am very inclined to agree with Frank. I'm 6'5" tall (195.5 cm) , so I have long legs for my height.
"It is inconceivable to me that bike frames vary from 48 to 62 cm (30% variation) whereas standard crank length vary from 170 to 175 (3% variation)"...