So in good years (when we don't have to fix a roof, or remove a tree) my mother's IRA can produce over $1000 a month. 

If you don't own the lot free and clear, it's still possible to use the equity in it, if when purchasing it you have a healthy down payment, and the seller agrees to "subordinate to a construction loan", which gives the construction lender 1st position.

I would like to make this an income producing avenue, at least a supplementary one.

I'm not sure how transport may twist or rack a wall, but I'm sure they are produced with better QC than a guy with a skill saw on a job site.

I tried the Central Appraisal Districts here in Dallas/Denton & Tarrant and have not been able to produce a cash buyers list if its even possible.

As long as the cash flow exceeds all expenses by a healthy margin and increases over time, do you really care that much about price fluctuation?

Have the owner produce Schedule E from his tax returns for the past couple of years to see the expenses being claimed for his tax deductions ... 25% is too low.

You would be better off wholesaling or flipping the properties to create operating capital until you are in a position where it makes sense to take some of your money off the table and stick it into an investment that will produce passive income.

I want to flip houses with an emphasis on energy efficiency and green, healthy improvements.

Our budget here is the same.Once all the internal bits are done we will reside the building - and are planning to add another 1" of polyisocyanurate hardboard insulation {which will require removing and resetting the windows we just installed to adjust for the new wall thickness ... a little rework that we have not found a way to avoid {yet}]Once all the above has been completed, we will conduct our "post retrofit" energy audit to see if we hit our target of scoring 75+ out of 100 with fewer than 3 air changes per hour.As you stated, the long term goal is to keep our buildings attractive to tenants by making them healthy, efficient and modern (while retaining their historic charm) homes as energy costs rise.