That would very interesting to see a C-series in the MPA, I never really thought it would be that commercial viable due to the competition with the P-8 and to a lesser extent the P-1. However it seems there is a distinct need for a guess green/ blue water capable MPA. An air-frame that will mostly operate close to shore loiter for a long time, but also have the ability to go out into the deep ocean. I think Saab tried to get that market going with the Swordfish MPA idea however I think to many forces believed it did not have the necessary endurance either fuel/coolant, sensors, or weapon load out.
Perhaps with the idea of NATO nations have strong defence ties and mutual security concerns, this green/ blue water MPA could be shown to be wanted by say the Netherlands, Poland, Germany, and maybe even Sweden. I believe it is possible but unlikely however considering how most pan-nato things work out, extremely over budget and extremely late in deliver.
On a side note I always wonder why the federal government has such angst with supporting a stand-alone MPA platform for C-series they could have partnered with say Lockheed or Saab. It has been obvious for years that federal government wanted to support the C-series financial so why not use the excuse of national defence to do it. It is the perfect win for any federal government either liberal or conservative. Support the troops, support high-tech industry, pander to Quebec, and support "middle-class Canadian families."; just my whole two cents on the matter.
While this is the RCN thread and not an aircraft thread, I do feel it pertinent to reply here. Further discussion on MPA or other aircraft should likely be done in a relevant aircraft thread.
When discussing the introduction of a new MPA design, there are plenty of airframe platforms available to serve as the base, so the platform is really not an issue. Where the problems usually occur is in the fitting and integration of the avionics and weapon systems. Typically the larger and more capable the desired fitout, the more complex and therefore more difficult, costly, and risky the design and integration will be.
While a 'green' C-series airframe could serve as the base of an MPA, if the desired end goal is to have a sensor and weapons performance comparable to that of the P-8A Poseidon, then such an aircraft is going to require some significant design work and cost, and the mission systems themselves are going to have to be advanced and correspondingly expensive.
From my perspective, while it could possibly be done, from an economic standpoint the idea could well be a failure since any such design is essentially 're-inventing' the wheel to compete with the P-8A Poseidon, or the P-1. Given the difficulties Airbus Military is still having with the A400M programme, I cannot imagine the company wishing to attempt something as complicated as an advanced MPA fitout without obtaining guarantees from future customers first. After all, Airbus had proposed an MPA-version of their A319 as a competitor to Boeing's P-8 Poseidon to replace the P-3 Orion, and as a replacement for Atlantique 2 MPA, but AFAIK the proposal never really took off. By the same token, given the A400M difficulties, I doubt potential launch customers would be all that comfortable placing themselves into a position where they are paying to develop a new aircraft which might not meet desired specs when they are needed, if ever.