I have a four foot long snake that's still eating mice, so if that's the only issue, you have a much larger range to choose from! However, getting back to our small snakes- Sand boas and hognoses can eat frozen mice, usually. You'd want to buy them from someone who was already feeding frozen. Ringnecks and rough greens are invertebrate eaters and aren't really good beginner snakes. I've heard that african house snakes (Lamprophis?) stay small, but I don't know if they stay 10 gallon small.