I was going to suggest something similar to Freckles... depending on how much money you have to spend, there are a few different types of sewing armoires that will completely close up with all your stuff inside of them. You might have to figure out a way to lock it up, or close it off, so little fingers won't get in there.
Rather than a credenza-type, this is more what I'm talking about:
It's gotten some good feedback on Pattern Review.com.
Here's a really pricey setup - looks nice though: