Yup, you can get longbow limbs. One reason I bought it is so that my son can shoot it in a few years. I figured I could get some 40# limbs and let him try it out.
This sounds like I am looking too far ahead since he is only 6, but he can almost get my wifes 43#@28 back to full draw. I know he is nowhere near the 28" mark, but when he can shoot the 40#@28", I will hand the bow over and let him get prepared for hunting. He shoots a 25#@25" Prodogy now. At the last shoot, he won his division and actually scored higher than 85% of the adults. He is quite the shot with a bow.
God Bless,
Nathan