I made a bunch for my kids and their friends and used Dean Torges kids bow article as a guide. He recommended taking a flat swan board of 3/4 (I think - check this measurement) hickory and cutting strips (maybe 1/4 inch thick - check this measurement too). The strips cut from the center of the board will be flat sawn and the strips cut from the edges will be closer to quarter sawn - nope - got that backwards. Glue a quarter sawn strip to a flat sawn one, add a handle piece, and tiller the width a little and the belly a little, blend the handle fades and you are in business. The length was 48 inches. A typical hickory board, 8 feet in length and 7-8 inches wide made upwards of a dozen bows. I think I still have one of the blanks lying around, if you cant find the Torges Article and need the measurements. The bows finished out between 15 - 35 pounds, depending on how aggressive you tiller the belly.
They take a little set, but for little kids that just makes it easier to shoot, IMHO. Also, not one of these bows has broken. The kids themselves decorated their own - some very extravagantly and other with just shellac. You will spend more time waiting for the glue to dry and assembling dowel arrows than you think.
Good Luck. Russ