I thought of a crazy idea at work today, daydreaming while customers browsed very very slowly...
Robotic plushy accessories!
When your Tamagotchi becomes an adult, you can buy a robotic plushy that matches the character you got, and that has a dock for the Tamagotchi unit - like a pet pouch with moving parts! When the character has needs, the plushy can make sounds and move to indicate that you need to attend to it. Meanwhile you get a soft thing to cuddle that resembles your character.

This is kind of like a cross between Furby and Tamagotchi.
At first I imagined it at standard teddy bear-size, but I think it would be more practical and portable if it weren't too much larger than the Tamagotchi itself. But then I wonder how difficult it would be to make robotics that small.
Wouldn't it be cute to have a little plushy Kuchipatchi in your purse or whatever, making little noises and wiggling?
I think if they were ever to make that, the line of Tamagotchi units would have to have much fewer characters on them than the current trend, so that you wouldn't have to buy a bazillion plushies to make sure you can match with whatever character you get.
I would probably wake up on time if I had a robotic plushy Ojitchi wagging his legs at me and saying "I'm hungry" in Gotchi language (like on the CD-ROM!).