My SBLOC requires that I pay it down to $0 once a year and keep it at $0 for one whole month.

My area is relatively low crime, but had one place that someone broke a window to get in.... probably a homeless guy looking for a place to sleep....got scared when neighbor turned light on.I put in a SimpliSafe unit... portable, easy to set up, multiple options- you can use a webcam and get alerts on your phone and future tenant can pay for full service if they want. 

I asked if there was anything else we could try, he got very angry and demanded I pay him in full.

All users are initially signed up on the Starter plan, which is free and what you have access to initially as a BP Pro member.

With the exception of building a trailer on the property (these are hard to finance), this sounds like a good plan AND if you are using it for your business AND your business pays more than 50% of the rent (if you have more than 1 tenant), then this is a more financeable property in the eyes of banks and credit unions as it would be consider a commercial "owner-occupied" property. 

I have spoken with them a few times, they are unconcerned, and happy to have me just pay the interest every month until it converts.

Imagine making millions of dollars over the course of your career and then having to pay 30-50% every year to uncle sam instead of compounding that cash over time.This is exactly what real estate professionals have learned to mitigate.To reduce their taxable income, they just buy a building every year, do a cost seg, and use depreciation to reduce their tax liability dramatically.Their personal wealth snowball grows much larger and much faster than their W2 counterparts who give most of their money back to the government each year.Following this strategy as a real estate professional is one of best ways to end up with a much larger net worth at the end of your career.

People in 1981/1982 were angry they were paying 18% interest.

The hang up is getting deals formally drawn up.One idea:- I buy the property and pay 25% DP, then they provide capital after the closing and I pay them P&I over 5-10 years.

That will increase your material costs for the job and is the contractor paying for the material in their bid or are you paying for it and paying them a labor cost.