i would say if you were GP on this hypothetical deal, then go ahead and do it. you could do a few more deals after this one and pay off the loan faster. if you are simply a LP, its risky since you have no control on how the deal goes. i did a similar strategy with buying a duplex but i have full control of the asset and how it is run. if you are going to be passive i would try the solo 401K route.   

It is simply a thermometer that reads the market temperature.

When it comes to actually securing a contract on a home that appears to meet your criteria, here are some tips (outside of simply raising the price):1.

I was simply buying and selling homes for myself (not for other people) but I exceeded the numbers allowed w/o a license.  

A period of several months (often 6) following the expiration of the agreement serves to protect agents from buyers who will simply cancel the buyer agency agreement after a suitable property has been found - just in order to avoid paying the agent a commission.Put more simply - it's a kind of "loyalty" agreement.

There are flippers who simply cover up issues rather than fix them in order to make a quick buck.

This seems pretty simply but you'd be surprised how many people can't defend their claims as to what the numbers on a deal are. 

If you end up needing those dollars, you can always pull them back out of the line of credit, but as long as you don't need those dollars, they're going to pay down your principal and interest costs.People use this strategy to pay off houses in as little as three years, and it really works, but if you simply want to use it to build up equity for an investment purchase—which is how I use mine—you can withdraw a huge chunk when a good property comes along and use the equity in your home to buy an investment.

Otherwise, it will simply impact your income and you will pay based on your income tax level that year. 

@Amanda PoltonYou should find a good investor friendly agent, modify your criteria, or start sourcing deals yourself for a duplex that makes sense for you.