@Joe Westmoreland
I understand your predicament, it's quite an interesting dilemma and I would like to offer an alternative way of looking at it... Allow me a couple sentences to set it up:
How much would you need someone to pay you to clean really nasty, smelly, poop-all-over-the-place toilettes? I'm not talking about once a year when your rental unit turns over, I mean 9 - 5 job and all you do is clean someone else's $hit. For me, I would probably do it if someone paid me $250k per year. Any less than that and I wouldn't even consider it. That's what I value my time as. However, if you were to post a job listing on a web page for janitorial services, you would probably get some responses for $10 - $15 / hour (maybe even less in some areas of the country). Think about that for a second... because it's NO DIFFERENT than what you're asking a partner for.
If you feel that 50% of the profits is fair for someone doing 100% of the manual labor, but not having to do any of the backend (financing, finding the deal, legal structure, etc.) then that is the structure YOU are willing to pay for. Your partner may feel the same. For me, I know how hard it is to figure out how to put together a deal in the beginning. It's not easy to get a house purchased with enough room to make money, arrange the financing, have legal structure to protect your assets, facilitate the sale, handle the accounting, etc. etc. etc. Once you do a couple deals, all of this becomes routine and it seems like you are "signing a paper in the beginning" and not much else, but you have to keep in mind how much work you did to get to that point. Not only that, you have to keep in mind how many people try to do the same and fail. You are basically taking the hardest part of the real estate business and streamlining it for them. The rehab is generally the easiest part of a flip in my opinion, especially if you use the same materials for each project.
My opinion, 50% is too much for doing a rehab because there are tons of contractors that are willing to do the work for much less and the quality of work is just as good. Think about it: if you have a $30k profit flip, are you willing to give up $15k just because you can't raise another $25k for rehab?? If you have a successful flip under your belt, I can show you 10+ people who would be willing to lend you money at 15% interest for your rehab. Let's say a rehab costs $25k and you borrow it for 3 months --> $312.50 per month x 3 months = $937.50. So you give up $15k to save $937.50?? Maybe you can't find anyone willing to lend you the money at 15%. So double it, pay them 30%, your cost is a little over $1,800 which is still way less than $15k. Do you know anyone who would love to make 30% on their money short term??? It's possible to leverage your time and experience by hiring someone else to do it for you and pay them with Other People's Money (OPM). Just another way of looking at things :) Great job on the flip by the way!