Originally Posted by
carleton
Oh, I never answered the original question.
If the frame is too big, swapping cranks won't help.
Frame sizes are like shoe sizes. If they don't fit, they won't fit.
^ That's the story, zap. I don't know how shorter cranks is gonna make a too-big frame any better for you, unless you're in a seatpost totally slammed but you're still hyperextending situation. Then I reckon the short cranks will help you shoehorn yourself onto this too-big frame.
Wear shoes with thicker soles, look for the saddle with the lowest profile - these methods would be cheaper than new cranks.