When my DS was about 3 years old, I made him some alphabet blocks with my DH's tools (and some of mine). I got the patterns from the stationary store, they came in several sizes. I think the ones I used were 5 inches high, and for quilts I believe they would be easy to make as applique.
i can just see them, either solid black on brilliantly colored backing, or bright colors on a black block. Thanks for the idea,
my DGD just told us she was 4 months PG and counting!!