For duplexes or larger, I'm not aware of any programs currently. 

On rentals, making them "durable" is a larger consideration.

I have also flipped two houses in the last few years which made a good profit but took a ton of time/energy while they were going on.

At the time of shopping (2012-2013) I wish I bought a duplex or larger.

The thing I'd be thinking more about, rather than offending someone, is if you are wasting your time and energy here on an offer that has zero chances of being accepted.

Or other problems with liquidating down the road to try and invest into larger real estate?

I'd guess so - I got mine funded in Sept 2017- I had 3 choices from the lender -- 3 yr rate lock, then adjustable, (either 5 or 7 yr rate lock) then adjustable or fixed for the life of the loan (25 yrs)5% at that time was what they were willing to do for the 3yrs, 6.75% was what they were willing to do for fixed for the life of the loan - they were one of the larger SBA lenders Id presume and kept it in house.

Compare the two and in both cases, the total net gain is much larger with the CA investment.

For a larger portfolio of conventional assets, it is best to do that in a separate IRA.

But if you get into creative financing, larger deals than basic SFH, or have partners, then you will definitely want to have one at the ready.