Seller Assisted Flip?

[Terrell Williams]

Has anyone ever worked with a Seller to flip their home?

Here's what I'm thinking... Seller has a single family house worth about $60k as-is. He owns it free and clear with no liens. I've offered to buy it for cash for $60k - they rejected my offer. The house has a ARV of $200-$220k. Is it OK to offer to partner with the Seller by offering $60k to rehab the place and to list it myself? I'm a licensed Realtor/Investor. In essence we would split the proceeds after its sold. We would both have $60k into the deal for a total of $120k. After it's sold at say $200k, we could split the $80k evenly.
Has anyone done anything like this "seller assisted flip"?