Carpets are great snakes, a tie with boas in my opinion.
If size is an issue Irian Jayas are I believe the smaller of all the Carpets I know of.
Ask to handle the snakes if you can find a local breeder or go to an expo. Some hatchlings are less nippy than others, I chose my I-J due to her very confident disposition. She settled very quickly when picked up and started taking in the changes in her surroundings.
She has not struck or bit me once yet, I wouldn't want to wave a hand around that smelled like prey though her food response is very strong.