Becaue I have bent several cheap aluminum unicycle cranks,
I have decided to use quality bike cranks. Moreover, It is cheap
sometimes and can be bought as a second hand material.
I have tried shimano deore crank first. It is relatively cheap.
It was about 40 US dollars. But my friend sold chain rings for
me to bike users, so I can buy it about 25 US dollars. 
I have sawed out spider. And final appreances are here wilduni.com .
I have a plan to use it for next low weight 24" muni. I need
lighter one, Because I think current KH "24 is somewhat
heavier.
Any comments? Let me hear your opinions. Thanks.