I would definatly get rats over hamsters etc I grew up around pet rats at a friend's house
This is why people don't get them as pets because they think they are smelly and full of disease, so are most wild animals!
I used to have a mouse who I would have trained if I had known it was possible then. He lasted 1.5 years and today I got his old cage out to get his ball out to give to my friend and their hamster

he was called sweet pea. The dog was rolling the ball around and acting like he was in there...eeeew I need to give that a good clean if she can still smell him! (it's been in the shed and don't worry I didn't purposely try to stress my dog or my mouse out!).
He was such a character but I think he was a bit lonely. I got him off a friend who had mice, and one of them decided to have a sex change, was meant to get two but sweet pea was the only one they managed to contain. He was so tame because of always escaping then being caught and handled to be put back in his cage when he was still with his family. Infact he was on the loose for the first day in our house because the cage was all wrong for a mouse, he was so tiny! It feels like a little dream now, I miss him! I knew the end was coming before it came, then when it did his bed box thing was so cold
I actually find small animals harder to look after, or maybe it was because he was soley my responsibility. Or maybe I'm just terribly lazy! Urgh I feel all guilty now.