Hi BP,I want to roll my ira to SOLO 401k because it sounds better in most ways to compared to self directed IRA. 

There are many SD IRA companies mentioned in the BP community.

GO after the ones with most return not to be slum lords nickel and dime every low housing.....Open IRA for your children as soon as they have FICA number etc.

@Eric TrompeterA lineal family member such as a parent or child could not use their IRA in a deal that benefits you in any way, which is sounds like this would.You should definitely work with a real estate attorney to draw up an agreement. 

I need 2 things, the confidence that performing a sub-to deal is within the boundaries of an IRA, and also need a contract with the verbiage (I'm in Texas).

There is no solid IRS opinion either way.The IRS rules prohibit the conveyance of benefit – directly or indirectly - between an IRA/401(k) and a disqualified party to the plan. 

I'm about to pay an HVAC contractor to install central heat/air in a SF rental owned by my SD IRA (and not held by an LLC). 

@Benjamin CookIf the 401k is from a former employer, it can be transferred to an IRA, or to a solo 401k if you are self-employed.

The good thing about this strategy is that when you refinance you don't have to come up with downpayment and closing costs can be financed into the loan.Open business lines of credit to finance quick purchases (that you can refinance) or downpayment: make sure that they are legit companies and don't charge upfront for application fees or transaction fees.Locate private lenders, like individuals looking to partner on deals to get higher ROIs, or institutional private lenders: these are companies or individuals using their IRAs to fund real estate deals.These are just some suggestions.

Areas that I am familiar with are the normal tax write off stuff and depreciation, 1031 exchanges, and self directed IRA.