The contractors who do work for me have zero issues with me sourcing the material if disclosed up front and not holding them accountable for any material issues.  

For the proceeds I have to pay seller I would have to issue him a 1099 right?

There's a good chance the issue(s) you face has already been discussed and answered.Ask questions in the appropriate forum.

Have you run to ground all the more common issues?

So what exactly is your issue here?

My tenant had an issue with the 1-year old dryer working.

Maybe call those owners and see if they've had any issues?   

If you sell directly to a homeowner, the issue can come back on you and bite you in the a...  

Mobile closing anywhere?

@Clark Harbaugh, Given the favorable tax rulings over the last few years (in particular revolving around trusts and their equaling a beneficial interest in the underlining propery) the IRS has actually been much more lenient (or at least silent) on these issues.