Non-institutional, I would consider, an individual lending out of their IRA or something similar.

I have a self directed Roth IRA that IRA services set up and they are the custodian.I have a solo 401k ROTH that's setup by discount IRA. 

This is slightly related but may help.With a Roth IRA you can take the principal out at any time tax and penalty free. 

@Mark Nolanthere is a chapter on Self-Directed 401(k) AND Self Directed IRAs.

For example, a high level member's rate is 3 + 13 and NO profit share.Additionally, investing in the fund as a lender is something anyone (who, perhaps, might be looking for a better ROR in their self directed IRA) can do.If it's something you're still considering, just call in and talk to someone.  

When I broke my 401k out of jail and rolled it into self directed ira, I planned to continue buy and hold with financing. 

@Manny RiveroAlso, take a look at IRA Wealth.

IRA?

Yes you can do that scenario but you want to be aware of IRS Section 121 regarding capital gains tax  If you occupy the property as your primary residence for 2 years during the 5 years prior to selling it, you can get up to $500k tax free.But if you don’t intend on selling it within a couple years, IRAS Section 121 won’t be that relevant.Check with your CPA regarding tax guidance. 

This includes 6 months of personal funds and 6 months (including salary expenses to myself) in my business account.Tier 2 - 6 months+ ROTH IRA.