Part C1152 at Ceeway seems to be the best option I have seen. I haven't bought a set yet but the long plug-in section seems ideal. The angle is the biggest problem but it is usually pretty easy to select bamboo with a kink at a node so that you don't actually need the angle in the metal.

Another option is to buy four of the carbon seatstay adapters from Nova and drill a set of the aluminum road dropouts to bolt on. The shape looks like it would interface perfectly.