.. you are not able to find the rigth size, or...
you have enough time but not enough money for them, or...
you need real though ones, or..
you just want to enjoy with new ideas, and..
you are able to build..
then maybe this link will provide some ideas to make you happy ;)
I specially liked the hinges ones.
Btw this is my first post so if is misplaced plz just move it. And pardon me my bad english :)