Poor people don't use Android. They need what the OP is advocating. That's the whole point.
Its actually a fairly ill conceived idea. Even downloading just headers for a lite client requires 20MB of download at current....how do you expect "poor people" to do that on their Nokia? This doesn't mention the CPU power needed to do the crypto stuff (will probably require 32-bit for pub-priv key)
Anyway, the prices for a no-contract Android at Walmart are just $50. No doubt these prices will fall faster than engineering effort into getting pub-priv key cryptography running on a 8bit micro.
When I say poor people, I am talking about third-world, living in slums poor people. Not college student "I only eat Ramen noodles and live in a studio apartment" poor, which really isn't poor at all if people had a grip on reality.
$50 is a monthly salary for most of the world.
Anyways, liteclients can even do without headers with the right node configuration. I don't see any reason why we can't get Bitcoin into the hands of Africans who transact with Nokias as their means of living. The solutions are feasible.