Some of my other rentals are newer homes, circa 2003-2005 with decent major components (roof, furnance, etc) and have not come close to needing the 50% rule to make solid cash flow, Yet.

What are the key components that are essential to learning a market that one is interested in doing fix and flips in?

And if you wish to have a checkbook control that truly self-directed Solo 401k offers you can add an LLC component to the IRA to gain checkbook control. 

It has nothing to do with innovation, profit, care, compassion, forethought, the deficit or any other sane components..

Bill Gulley-Ken and I talked about this as this is a component of his program.

Taking the money of hard working Americans and giving it to the bankers; socialists; radical environmental causes (like the proposed cap and trade); and taking ownership in our largest companies is particularly offensive.

However, you guys shouldn't be so quick to dismiss Nobel, I hear W 43rd was lined up for a Nobel of his own for outstanding environmental work (excellence in brush clearing while holding highest office) but unfortunately that didn't go through...

Oil spots large enough can be tracked into the house and ruin the carpets, they make the curb appeal look bad and are an environmental hazard that could get you fined by the city.

Was it a matter of popular style back then, was there some sort of money saving component?

If you do most of the above, you can advertise your rental as water and energy efficient- most tenants will only care about the money they save, but being environmentally friendly is desirable to some small subset of people.