I hope you can take more hints from permacoin. There is an important economical point in permacoin's whitepaper:
"The expected reward per unit of work is approximately constant, even for very small investments of computational effort. This prevents large participants from monopolizing the system and driving out ordinary participants."
Maybe I don't have a deep understanding how filecoin works, but as far as I know if you don't have the storage capacity which can even reach the current difficulty then you have an expected reward of 0. Maybe it's a non-issue and the difficulty will never reach let's say 10MB, but if it reaches 1TB then it will be really hard to hop in the mining business.
"The expected reward per unit of work is approximately constant, even for very small investments of computational effort. This prevents large participants from monopolizing the system and driving out ordinary participants."
Maybe I don't have a deep understanding how filecoin works, but as far as I know if you don't have the storage capacity which can even reach the current difficulty then you have an expected reward of 0. Maybe it's a non-issue and the difficulty will never reach let's say 10MB, but if it reaches 1TB then it will be really hard to hop in the mining business.