I have hickory bow blanks already glued up if you are interested. They are Flat Sawn hickory bellies and QS Hickory backings. They are glued up with reflex built in. All you need do is add a handle piece and tiller. They are 48 inches long.
I use these blanks for kids bows in the 20-30 lb range, so a 15 lb bow for a 5 yr old could be gotton easily with out the need for any further backing - as they are backed with QS hickory already. As for the purple, dye or paint, or maybe find a purple tie, cut it up and glue it down. My preference would be the dye as you can still see the grain thru.
If interested, I will take some pics. I would be willing to trade for some sinew.
Russ