Some people would do it without a cushion and just finance the rehab on a credit card that doesn't ask you to pay it back for a year. 

The $75k pays off your $50k hard money loan, and gets you your $25k rehab cost back (or pays off that debt if you financed on the Home Depot card or whatever).

My husband's first boss bought his first house on a credit card, since it was a better interest rate than the 18% on the open market.  

I have some significant debt, and I've put some of the project expenses on 0% APR credit cards to bring it to completion, lowering my credit rating.

Credit card?

Can you by with zero percent introductory rate credit cards and cash flow payments! 

I go so far as to give any of my clients my Lawyers business card any time they say “I’m going to sue you.”

they owe everyone, like utilities, cellphone, credit cards etc.

You could attach picture of the property, the Lease, manage account balance easy, add/remove fees, and tenant may use the Credit Card for rent payment if they have emergency (Cozy will charge them some fee).  

I'm basically looking for a site that I could direct my tenants to and they can use their debit card to pay rent.