If you're going to make a custom top don't use 1/8" glass, 3/16" is much better for that purpose. It won't sag in the middle like 1/8" will, though a 10 gallon tank isn't all that wide...
I have some vinyl channel lying around if you want to make a sliding glass top with 2 pieces. I used it on a 30 long with 1/8" glass, then eventually bought a regular versa-top for the tank.