I'm working on a similar system, but it's quite a bit simpler, can use national currencies, and does not have supernodes or Byzantine fault tolerance http://altheamesh.com/blog/universal-payment-channels/

I haven't completely specified the routing part yet, but I think it will be quite easy to extend Babel to incorporate cost as a metric. Due to Babel's network size limitations, it won't work as a big bad global mesh, but should work well in the smaller mesh networks we see today.