As it stands the kind of people who want a smaller phone almost by definition need to be a bit savvier than the market in general to know such a thing still exists and along with that will have greater skepticism towards Android phones having any kind of post market support.
It'd basically have to come from Samsung to hit the all the price/quality/trust requirements. Feel like they've already got a lot of the pieces there with their corporate targeted XCover range just shrink them down a bit.