I've looked into similar ideas. The hardest part I've found is finding something with enough depth to create a decent amount of floor space.
A lot of book shelves, cabinets, hutches, etc...have good width and height, but they are really narrow depth wise, which doesn't allow for much floor space for the snake. They'd just be too narrow. It would be tougher to find hides and water bowls to fit, etc...

That being said, I'm always looking and am determined I'll find something eventually. I'm just waiting for the right piece to repurpose. If I'm going to do it, I'm going to do it right.