We recently heard of Truth in Equity via another real estate podcast and were intrigued enough to do some research about them. Turns out you don't need to pay them the 3000 dollars to do this strategy. You need three things to make the strategy work: a line of credit, a decent credit score, and a decent amount of cash flow left over after your bills are paid. The more money you have left over after paying your bills, the faster you can pay down the HELOC balance after using it. Of course, this requires you to use the LOC as a checking account from which all bills are paid.
We are in the process of doing this. Our plan is tweaked as follows: obtain HELOC; pay down principal on our primary home with a lump sum payment from HELOC, dump all paychecks into HELOC account, use another credit card to pay all monthly expenses, then use HELOC to pay off credit card bill. In a few months, the HELOC balance is back to zero and the process is repeated.
There is a lot of information out there about this. I think it can be done, though, independent of the mortgage accelerator company if you can find a good HELOC product and you're diligent in managing your finances.