It can be a tailsitter, why not? But after reading the PDF that you posted the first thing that came to my mind was the unfinished idea of a landing, especially in a bad conditions. I noticed it several times in countless aviation projects where the biggest effort was to take the vehicle to the air and authors forgot to think about how to safely and routinely land. For your craft it is even more important, because the only possibility to land (and survive) is 90 degrees descent angle. You cant glide with a relatively high forward velocity like the helicopter in an emergency can do. Your description is about the landing when everything goes perfectly, but what will happen when some error occur?
Another disadvantage, related to landing is very high center of the gravity. I know that the current description is aimed to show general philosophy of the idea, so it is not engineered with all the details, but landing gear/device seems to me as very straight, more like on some rocket. The legs should spread wider and they should have some sort of spring-back. Next step will be the internal arrangement. I don't know if you have in your mind some, so I tried to imagine some simple one. Engine is on the bottom/back part, tilting cockpit is in the middle of the propellers and probably the fuel can be on the top/front. Another fuel tank should be just above the engine and the fuel distribution can be used to balance the whole vehicle. For example during the landing the residual fuel should be only in the bottom tank, but during the forward flight the fuel should be consumed from the bottom/rear tank firstly and only after from the top/front tank to keep the center of the gravity somewhere in the middle of the propellers.
For the manned variant it is critical to have a lot of windows and at least one TV camera. Okay, once again when everything goes perfectly, this process can be heavily automated, but what during the emergency because for example the system failure when the manual landing will be needed? The pilot will be very unhappy to look through some two small windows through the rotating blades to the ground. I had the opportunity to try Mi-17 in the intermediate conditions and I must say that it is not so easy as it can look like. And the Mi-17 is perfect and stable helicopter with a very good view from he cockpit. It is very different to fly IFR in a comfortable modern airliner compared to your rocket-like rotorcraft.
That are a few points that you should think about before any demonstration. I hope that my point of view will help you to take a different look to move forward. 
