WOW! Tablets for 4-year olds?!?!?
Ummm... I guess they also have to be small enough to be handled by their small hands and light-weight enough not to weigh them down?
This forum did an article on some small tablets being marketed for women (no offense to women, but they generally have small hands)
LG Planning to Launch Android Tablet in Q4, 3 New Optimus Phones
Or you can try the TINY but PSP-looking Arcos Five
Archos 5 Android Tablet review (Shallow Thoughts)
Since it's for kids, I'd recommend the Harris RF-3590, which, except for the glass, it VERY difficult to break
Rugged PC Review.com - Rugged Tablets: Harris RF-3590
Did that help?