Gotta give credit for trying something new... Any idea is good to try... But Design with Form following Function is a difficult task... The idea would be to look at the probs with what we have now with leashes getting caught on things...at times and make something better...
In relality... This is a good place to out stuff out... Since so many here put there gear in the strangest situations... Even the Kite Design can learn from the forum... I think... We use the gear to death...
Each loop of webbing and link can potentially get caught on anything from tree branches on a drag... rocks... sticks... fingers... bar ends... Footsraps....clothing so on... (Chunky) So I can see how trying to come up with something better than the regular tube mesh with bungie... Mystic neoprene covered leash can be tricky...
Maybe you can try some other designs.. too... and show us... It may come in with more function and cost even less...
One of the most complex issues to deal with are leashes that break... or sciccor clips that just open up and come off... and the kite gets loose.. in crowded areas...
You could get good feedback... Good or Bad can help...
Some things to look at
http://www.x-shooter.de/ XRR Leashes
http://www.mystickiteboarding.com/
Paul