You are asking someone to sell their house for below market value and they know you are going to make a profit off it, so if you aren't solving an issue of theirs then why would they sell to you?

And we’ve made more profit on each deal in progression ending with a latest where we netted about $65k on a pop top.

I feel like with good tenant screening you can get good enough renters who won't give you many problems (most of the time) and make good money off manufactured homes. my grandfather owns many and makes a great profit.

We can rent it for the duration and In addition, the property values will  likely continue to rise, and if we are overpriced, there is better chance of keeping our expected profits. 

.$40.000 - Purchase price$1.400 - Purchase closing costs$10.000 - Repair costs$2.000 - Holding costs$3.900 - Commissions$975 - Sale closing costs$58.275 - Total Costs$65.000 - Sale Price (I split the difference in your range)$6.725 - Profit before personal taxes $53.400 - Total cash invested (Total costs - commissions - sale closing costs)12.59% - ROI (again assuming no financing)The ROI is not horrible but one thing goes wrong or if you are off on your sales number by just 5% and you lose ALL your profit and take a loss on this as a flip.The property you are mentioning should be a rental based on the limited numbers you provided.

I don't know if you could make enough profit and still have enough to make the investor's risk verse return worth it.

(If you are going to pursue it, take me with you!

Or just advice before pursuing the deal .

I helped a Colonel in the army buy a home 3 years ago that fit this criteria and they recently sold for a nice profit.2) You can buy a small multi-family. 

I use Profit Realty, very happy with them .