The US Coast Guard have used C-130s for long range ops for decades, so there is a precedent, and one or two other nations have also undertaken MR/SAR duties. I think Indonesia and Brazil have.
As for VIP duties, the Saudis have at least one configured, as far as I am aware.
With the P-3 no longer in production I would have thought that Lockheed Martin would be really pushing a 'PC-130'. There are a lot of nations out there that cannot afford the Poseidon but will want something more than a C.295.