Definitely possible, considering Saiden Storm's Akatosh Mount mod for Oblivion. I would very much like to see a mod like this made. Paarthurnax and the Greybeards should definitely play a role in teaching dragons and riders the Way of the Voice. They could serve as the mentors of the order, while the player and Odahviing would be the first dragon and rider. Recruitment shouldn't necessarily be limited to Dovahkiin, however, as that would severely limit the riders' numbers. And, as pointed out, it should be made unique, distanced from Inheritance. Same basic idea, but overall a different story, different philosophy; the Way of the Voice should definitely play a role. Maybe use Sky Haven Temple as a base in Skyrim, just tell Delphine and Esbern to get the hell up outta there! Hold off on battling the Thalmor for now though, since Bethesda might have that planned for a DLC (you never know). Just my thoughts, I'm very excited to see this mod.