I assume a higher upfront cost as far as land purchase and the actual build but you would have a brand new house, instant equity and hopefully maintenance free for quite a while.

We did get much lower costs when we changed to minisplits but the initial cost is high.

Alternatively, if I can find a lower cost single fam home where I can cash out 100% of my investment I would do that but those have been harder to find recently. 

But from a moral & ethical perspective, you may want to decide at some point to just eat it and accept write it off as cost of doing business.

Quote from @Daniel Gould: So it appears to me that while there's a free plan available to anyone in Invelo but the BP Pro membership includes access to the "Starter" Plan which currently costs $41/month otherwise - so this is a notable "value add" to the BP Pro Plan.

In other words, you will incur the cost of demolition just to get the raw land.  

Going this route is more involved and that makes it more costly too.

If you have excellent credit and enough for a down payment/closing costs without totally wiping out your funds, I say go for it!

For example, if a property rents for $2,000 and costs $200,000, that’s a 1% rent-to-price ratio ($2,000 ÷ $200,000).

I would say for most people, the 1st position heloc is no a good bet, especially if you have a 1st mortgage rate of less than 5%.Using this strategy with a 2nd position heloc can be just as powerful, so you can have your cake and eat it too!