I also recommend Mantano Reader Pro for a great epub reader app.
Samsung does not make it without the phone part, but there is no rule that says you have to use the phone. Just put the device in airplane mode, then turn WiFi on as desired. I don't use the phone on mine, I didn't even own a SIM card when I got it. I did unlock mine in case I ever want to use it as a phone, but you don't have to do that to use it as a WiFi only device.
Otherwise, the closest non-phone device to it would be the Samsung Galaxy Player 5.0, but it is really no contest between the two, except for battery life.