In 1973 Ray Holland was granted a patent for a curved spar sled kite. The idea behind the design is that if you arrange the spars in such a way that they have somewhat of a curve (the patent is more specific on how much per a certain length is necessary but it does not have to be a huge amount) the action of the wind against the sail and the curved spars is such that it tightens the leading-edge thereby preventing a collapse. The end result is very effective and can be flown in extremely turbulent wind without fear of collapse. This also does seem to allow for much shorter bridles than would be normally recommended for sled kites (about 1.6x versus 3-5x the kite length).
Patent: __ US3767145.pdf
1/2 Plan template (by Mathew): http://github.com/mathewlippincott/TALA/blob/master/TALA_Kite/TALA-half-sheet-8.5x11.pdf
Kite with spars threaded through holes in the sail kite with spars attached via tape (like I decided to do on mine)
above pics from http://www.users.on.net/~maxtmp/kite/image/Hollan~1.htm
kite when out of the wind