I will either have to sacrifice location or quality in one way or another. 

Higher fiber quality/higher $/lb and less chemical costs! 

In general, retail will pay more and want a higher quality product.Build to rent is more utilitarian and they generally want a lower price.It seems that I can make more selling retail than I can with build to rent.  

Are their listings detailed with good quality photos?

We may be a little late to this, but we are available to manage STRs anywhere in the country and do it at both the best price you will find and at a very high quality.

Very few have been operated as a business...most are, at best, a hobby, where the Owner enjoys doing handyman work (often of dubious quality), at worst, an absolute "investment" Gamble, with no regard for tenants, laws, or much of anything but spending the absolute minimum while collecting the most money possible until their "cash cow" implodes.

Most quality PMCs will not manage these properties as they understand most owners won’t pay them enough for the time required and even then it’s too difficult successfully manage them.

I have found a Chinese manufacturer that will ship me a container full of counters, toilets, tubs, etc. and the discount is pretty significant, but between the low price and some language barrier, this gives me some concern about quality, correct measurements, etc. 

You can still conduct high-quality due diligence by signing up for remote property tours, checking comparable rent prices, running numbers on a few listed properties, or even by looking into local age, education and crime statistics.Then, assemble a local team of real estate brokers, attorneys, and property managers so that you have some boots on the ground.

Professional management.Tell me more please.What kind of rent and quality of the houses?