Both of you should go to a bank or mortgage broker and find out how much money you can borrow for a mortgage. 

@Christopher ColeSubject to is when you buy it subject to existing mortgage - a wrap is the second half a subject to where you then turn around and sell it to someone else and put a second mortgage on the property where the new borrower is paying you as well

We don't have total control of our money if options are limited as to what we can invest in.Yes, you can borrow from your 401k and pay yourself back.

You are talking peanuts.I once borrowed a piece of machinery from a friend valued at $12000.

@Guanghui ZhuIf these are land deals and you are not made whole after foreclosure in most states you should be able to obtain a deficiency judgment as you know the borrower is not living there and may own a primary residence.You could get a judgment against the borrower on their primary home and seek to foreclose on that propertyPeople tend to take things much more seriously when it’s against their home vs a vacant lot

If the interest rate is set at 10%, making 9 payments or 12 payments the first year shouldn't change the amount of the monthly interest..Are you borrowing $55,000 or $50,000?  

If someone needs to borrow money for the EMD, that shoots the risk through the roof.

it seems pretty low risk with selling my primary house with the ability to borrow against another one of my properties if necessary, but I am relatively new to any lending outside of a bank.  

This means that they are borrowing money at 6.5-7.5% interest rate to buy a 7 cap... which means either neutral or negative arbitrage between the purchase and the cap rate. 

@David Ingram that's not required by all lenders (in fact, I've never had a lender ask for this), but it might be required of some lenders...and it's possible more lenders are requiring it these days, since many are tightening their underwriting requirements.  ..whether or not lenders require it may also depend on the borrower's overall financial picture and DTI (I'd suggest asking your mortgage broker whether they require this of all borrowers, or just in certain circumstances).Also keep in mind that not all lenders/mortgage brokers are the same--if you go around to multiple mortgage brokers, they may give you different qualification amounts, different terms, different underwriting requirements, etc.