Looking good.
Just thinking whilst looking at the pics (dangerous I know), but I wonder...make fuselage, wings etc out of carbon fibre, use something such as GE H80 or PT6 engines maybe forgo any sort of crossover shaft (maybe use an electrical crossover as a limited backup), add in some good software...
As a thought, this might look even more practical if you were to move the engines themselves to the top of the fuselage as fixed mounts and then simply have small 'snub' rotating units at the tips (with electric motors doing the actual rotor/prop driving). Then there would definitely be no need for crossover shafts as all would be electric.
Now, make it a cargo UAV and we can start talking about me putting money on the table to start a production program...