Tamagotchi Dream Town Friends and TamaGo are pretty close to iD and later color tamagotchi's but i prefer if the screen can expanded to 2 inch or 3 inch would be great as even with 3 inch display(like Sony Xperia Mini) i believe the device still small enough to fit in the palm and pocket.
Definitely real tamagotchi as nowadays smartphone display is way too big for tamagotchi to fit in, even Sony Xperia Z5 Compact is still too big for it.