Just look at all these cheap handhelds at dealextreme:
http://www.dealextreme.com/products.dx/category.610
There are 2 that are less than $20!
Surely someone on these boards can figure out how to move one of those screens onto a wiz, or move the wiz guts into that case. They are so cheap that if it doesn't work, big deal - you paid some money to learn about electronics.
I'm currently working on a different project, but I might try to look into this as I love the Wiz and don't want to lose it because of screen problems. Mine still works fine though so its off limits for testing. I might work up the courage to offer to pay for some broken units just to tinker.
Someone that has opened the Wiz case can answer this - how is the screen attached? Is it soldered to the board or clipped? If there are any, are the wires to the screen somewhat obvious as far as what they go to on the board?