Martin makes both the Cheetah and the Leopard in lower draw weights. Nice thing about the Cheetah is that the draw lengths are available all the way up to 30" - most of the other reduced draw weight bows are designed for shorter draws.

I also have a Fred Bear Element 50/60 turned down to 43.7 lbs for my son (six turns out on the limb bolts). It shoots very nicely and groups well.