It's sounds far-fetched, but I want to understand it if it's actually do-able.  

On the commercial side this is still tricky because we are talking about 100% financing, but it’s doable.

For a new investor managinging a C class property is a challenge but doable.  

Very doable if your projections are correct. 

But it is do-able, the best time to get started is right now AND you are here on BP- Awesome!

For houses in the $150K to $190K this has seemed very doable in terms of down payment/mortgage.After looking at closing costs though I'm worried that the numbers may start to fall apart.

Is $25-$50/SF doable if I put in sweat equity where I can, and buy materials myself? 

Because most buyers decline to pay a buyer's broker fee directly, my competition is vastly lessened on these transactions.So, while the percentage of doable deals is still very low in this category, when the rare great deal appears my competition is vastly decreased.I will give you a real example from the last few months. 

So, i am thinking maybe to start some kind of partnership with someone local.Again, rough example: in the partnership i provide money for down-payment and the other provide the loan for the rest and split the monthly cashflow.What are your thoughts, is this do-able?

I encourage you to proceed when the worst-case scenario is still "doable" for you.